I also remember people hacking IIS, SQL Server, WebDAV or exploiting one of the hundreds of RPC/DCOM/LSASS vulnerabilities in Windows, the servers were then used to start private FTP servers used to sharing warez. At least that was something the FXP community did, the FTP servers were then filled very quickly from other FTP servers (hence the name FXP, File eXchange Protocol). Thinking back to it, it was quite astonishing how horrific Windows security was, to think that people (to this day even) are seriously considering Windows a viable server operating system still makes me laugh.