Apologies for keep thinking out loud.

A) The workbooks currently at ExelCalcs are for the most part simply formula, and that can pose a problem in terms of their value to anyone. The workbooks in essence contain functions defined in a worksheet, consisting of a parameter list and a calculated result.

These functions can be simply copy and pasted into more substantial design-solutions. In a more substantial design-solution however the parameters are the results of previous calculations and the results are the inputs to additional calculations which follow. The simplest way to link these functions together is to point a cell in a parameter list to the cell containing a result. Doing so however results in a lot of cells, simply used to link formula together. To remove these redundant cells, and save memory which may be a problem for many, requires revising the calculated formulas references to other cells. In effect it requires rebuilding the formula, hence may aswell have built the formula from scratch in the first place.

In a comprehensive workbook, one providing a complete solution to a design project, there are many issues to consider, here are just a few.

1) Variables have meaning within the context of a given formula and/or reference manual. When combined within a more complete set of calculations, unique variable names start becoming more important.
2) Named ranges are more efficient than running around pointing at cells or remembering cell addresses, and they make formula more readable.
3) A variable may be used multiple times throughout a workbook. When it is then named ranges start becoming important. If ranges are named then it is helpful to place the name in the cell adjacent to the value, this text label can then be used to create a named range. When doing this placing equals '=' after the name is a hindrance, additionally subscripts, letters of the Greek alphabet and other character symbols cannot be used. In effect back to the limitations of programming in a high level programming language like VB, Pascal, C++ etc.

This means that the text surrounding a formula obtained from elsewhere is redundant, and the cell references in the formula become redundant as the formula is linked into the more substantial workbook. In other words copying and pasting a formula from elsewhere is more or less a pointless exercise. If the user already as a reference book with the appropriate formula then they may as well type the formula up from scratch.

B ) The knowledge tree adopted at ExcelCalcs is potentially a discouragement to contributors, it is relatively simplistic. Calculating structural loads induced by environmental phenomena is not a miscellaneous activity, it is an important and essential starting point for the majority of structural design. Wind actions being deposited in miscellaneous is not encouraging for others to contribute more in this area, such as earthquake loading. Then there are other areas of design such as stormwater drainage and flood mitigation, pavement design, tension membranes, cable nets. But then in many of these areas can search the net and find more useful programs than Excel workbooks, but many of these programs could benefit from integration with Excel.

C) The current workbooks on ExelCalcs are indicative of the scientific/engineering knowledge and knowledge of Excel which the membership has. This is also potentially indicative of the technical level of the users and the amount of effort or approach they have to design.

The wind actions workbook for example is a simplistic interpretation of AS1170.2 wind actions. Simple because it only calculates the wind speed from one direction. AS1170.2 actually requires calculating the wind speed in all 8 cardinal directions and finding the maximum and adopting this as the site wind speed if building orientation is ignored. Terrain category, shielding and topgraphy are seldom constant around the building. Many new houses are at the edges of suburbs where they meet rural terrain. Thus one side have TC3 and on the other side something approaching TC2. However if the area is developing quickly it is permitted to adopt a terrain category for the developed terrain. In rural terrain the category changes with the seasons, long grass cerial crops when ready for harvest produce a terrain of around category 2.3, when harvested the flat ground is closer to TC2, but not really similar to the reference TC2 at an airfield/airport. A designer may wish to address such issues explicitly and mathematically, or by unexplained judgement call.

If the orientation of the building is considered, then calculating the design wind speed for the building gets slightly more complicated. For now wind speeds in four orthogonal directions need to be calculated, one for each surface of the enveloping rectangular boundary for the building. These orthogonal wind speeds are calculated from the 8 cardinal wind speeds, dependent upon which directions have an influence on the surfaces of the building. A tabulated approach would be more suitable presentation of the calculations, than a simple vertical solution down the page which considers one cardinal direction only.

None the less the workbook, I assume, gives an appropriate solution compliant with AS1170.2, if 'Md' is is not taken to be equal to '1', then the maximum for the site can be determined selecting Md with the next highest value to one, assuming all other factors are considered constant for the site.

The approach taken would suit the needs of many people. And there is potentially little value to be gained by any one submitting a more substantial coverage of the wind loading assessment.

1) The immediate submittal of a more substantial workbook may seriously discourage original contributors. Unless they adopt the approach: that the way to get a more substantial workbook is to provide some bait to lure the competitive nature of others to out do them.

2) A more substantial workbook may gain more criticism and less usage than a simpler workbook. Discouraging the contributor. And once again being indicative of the technical level of ExelCalcs membership and the type of effort they wish to put into design.

3) There are more substantial workbooks out there already in many areas of practice, though many are only available in exchange for a fee. AS1170.2 once again provides an example. John D. Holmes one of the prime contributors/authors to AS1170.2, and author of Wind loading of Structures, has his own Excel workbook available for sale at his website. But why buy what you can create yourself from the code. And once created why provide to others who are too lazy to create for themselves and who also don't want to buy what is available? Thus if know there are commercial products out there and the cost of such products, then also potentially know what cost others are being saved. But not in the business of developing software or competing against such commercial suppliers therefore not really interested in listening to criticism or preferences. If don't like go buy the commercial product, or otherwise fix it yourself or find someone else willing to fix. This someone else will probably charge a fee, and such fee will probably be greater than cost of buying what is already available. If have paid to have spreadsheets developed for a business, still even further reluctance to submit to a website. Then there are users and creators.

4) Submitting substantial workbooks to a new website which intends to operate as a commercial venture is also a discouragement. The site may not be here in a few months, and websites come and go. It therefore needs to be seen has having some staying power, and real capacity to distribute. (A website that arrives and collects and then disappears over night, but re-appears elsewhere selling what has been collected, is one danger. I very much doubt that is the case). But putting voluntary effort into something which may disappear because it is not achieving its commercial objectives is a disincentive to contribute much effort to development of its non-commercial aspects.

D) As also previously mentioned most users were attracted to ExelCalcs because of an email promoting XLC, they did not arrive here looking for calculations or to buy books. Books are expensive, and for many Amazon.com is a long way from home, so books take a substantial time to arrive. So everyday books I can get a lot faster a lot closer to home from local book stores, and therefore Amazon.com is used only for those books which a local book store has to order in any case. If a local store has to order, then the Amazon website is usually superior to any local website, and more information can be obtained about unknown books from Amazon then elsewhere. So Amazon is the closest website there is to going into a bookstore and browsing through the books on the shelves. However in terms of the need to purchase books from Amazon, that probably doesn't exceed more than a couple of times a year, and probably a lot less often.

Thus it may take a significant time before members of ExelCalcs start buying books, possibly 12 months or more. Myself, I bought several books from Amazon at the beginning of the year, and it may be some time before I buy any more, others may be in the same situation. On the other hand ExelCalcs may need to be prepared for a surge as people start buying books as presents around christmas time, or businesses unloading budgets around end of tax year (when ever that arrives in different countries).

Members arriving for XLC, also tends to suggest membership comprises of users not creators. That is to say the membership searches the web for what it is looking for and then either downloads for zero fee or pays accordingly. That means a large proportion of the membership doesn't own any workbooks to contribute. Since they came looking for XLC, don't own any workbooks to contribute, and are principally users rather than creators it also means they have limited skills and/or interest or patience for creating and setting up workbooks. They probably wanted XLC, to improve the presentation of those workbooks they are reluctantly using because their employers insist they use. It may take these users time to get up to speed and start creating their own workbooks which they are willing to contribute to a semi-public repository such as ExelCalcs.

E) As with the repository the knowledge structure tree for the forum reflects simplicity. As others have indicated the forum is the key to developing membership, and sustaining presence at the site. As Christopher Locke points out in Gonzo Marketing: winning through worst practices, the web is a market filled with conversations, and these conversations have more importance and value then any advertising. Locke is also coauthor of the cluetrain manifesto which can be found on the web.

If people are present at the website conversing and exchanging ideas, then a book reference may emerge and from that a book may be bought through the ExelCalcs link to amazon. One of the users mentioned above may make a request to a creator to set up a workbook, such a request may be welcome, and willingly satisfied without fee. The ExelCalcs repository being used as a channel to pass the workbooks from creator to user.

At present however, there is little in the repository to attract sustained attention, and there is little to discuss in the forum to attract and sustain attention. Topics in the repository like strength and dynamics are interesting once you get down to them, but first have to get down to such simple elementary topics.

To really get people talking and present at the site, need broader topics and some development projects. For example fields of engineering: industrial, manufacturing, mechanical ,structural, civil, architectural, chemical, electrical etc... Develop this in itself as a topic of discussion, what are the disciplines of engineering and design science? And where do such disciplines overlap?

Within each discipline could break down into other topics of interest. Such as within architectural engineering, could cover building structure, mechanical building services and electrical building services. Straight away, these three topics are within the scope of the larger disciplinary areas of structural, mechanical and electrical engineering.

But people engaging in these conversations shouldn't feel limited to conversation about Excel, XLC or the calculation side of things. The qualitative side of discussions is most likely to lead to purchase of books from Amazon, whilst the quantitive side is most likely to lead to creation of Excel workbooks.

The conversations are important for members to get to know one another and develop a community which they feel comfortable sharing their work with. (Noting that XLC is something akin to a plastic toy given to attract sales of something else, and it isn't actually given freely, it imposes obligations. The author of XLC expects to gain something other contributors are not expected to gain.)

So I guess the priority is to kick start the forum, get some conversations or debates going.
F) And then there is also the pareto principle. Just how many calculations are needed by any one that they are unable or unwilling to setup for themselves, and haven't already done so.