No, we don't have any of that at the moment (although some people are kind enough to greet you on your wall if they bother to do so).
If you meant something like a computer doing something like posting on your wall and giving you a brief intro, I'm not sure that's possible, and if it was it'd probably be hard to do (though I'll need Pokemaster to get a definite answer to that). If you meant something like a system where a mod greets you or something, the chances of the happening are basically zero. We already have to run the Admin on the PokeBase, manage the site, etc. and somehow having to go through a list of new users and greeting them seems a little pointless when 80% of them don't even do anything with their account.
As Once said, go ahead meet a few others in the chat room. And if you want to get a good idea of who some of our most active and well-known users are, check out our list of users. They are all very skilled players, and most of them are active, so you'll probably see them sometime in the future.