Generating a sitemap of 50,000 Topics will hit performance of the forum if generated on the fly.
As there is not a way to schedule tasks in Classic ASP it would need to be an admin option to create the sitemap if it were not to be generated on the fly.
The other issue is that unless the forum had URL Rewriting installed the file would be sitemap.asp.
You could use the FSO object to generate a sitemap.xml file, however, from experience find that many people running Web Wiz Forums have write permission disabled on the forum folder, which you should do for security, which means that could not generate a sitemap.xml file using the FSO object without modify permissions on the forums root folder, which is not advisable to do.
For these reasons mention above it may be best to have this feature as a add-on module rather than built in to the software.
Edited by WebWiz-Bruce - 24 October 2012 at 11:59am