Say you have an extremely OLD classic ASP application, written circa 1999. Your company's CIO has mandated that all applications be migrated to new (Windows 2003/IIS6) servers.
Stuff that worked in IIS4-5 doesn't always work in IIS6. Emailing using the old CDONTS.NewMail object is trouble.
To prepare for the migration, you want a single code base that works on the old and the new server. The following functions , based on the "SERVER_SOFTWARE" server variable, will help.