Our software can run on both *nix and Windows-based servers, using either Apache or IIS. That said we always recommend *nix and Apache over Microsoft’s alternatives. Because so much of what we do uses open source technology, we prefer to keep it that way through the stack.
Our relational database management system (RDBMS) of choice is MySQL. Although choosing a database can be an evangelical issue for some people, we try to avoid those kinds of discussions. Instead we focus on choosing the best tool for the job at hand, and so far we’ve never had a project that MySQL couldn’t handle, either in terms of complexity, scalability, stability or reliability.