How you found the community or the earliest community experience you can remember: First taste was thetreacletart's Still Life story, then went lurking in ff.net looking for interesting Remus stories and found cruisedirector's Coffee and Chocolate stories. I think I found the community through her account there.
Why you ship Snape/Lupin: Because Snape and Lupin are two of the most interesting characters in HP and the chemistry is just lying there, waiting to be tapped.