ASP.Net compiles into dll so that is probably it. The only other web language that compliles, that I know of, is JSP (JAVA) and those files are .java I believe.'Then again windows has had dll files long before .Net.It is possible, especially since htey are using CGI, that they have COM files (c/c++ compiled to dll).Really there is no way to know for sure from just looking at the site.