1) Be very careful with this. I would avoid using any body filters with the email filtering capability of the web panel... and if you do use such filters, make sure to move the messages to a different folder rather than deleting them outright... otherwise you may have mail unintentionally deleted (if, for instance, someone from the a town like Scunthorpe or Fuckingen [actual towns¹] emails you with their address). I'm pretty sure that procmail does support word boundaries (like) which would work a little better, but you can't use regexps in the email filters panel. I would suggest using something like Spamassassin or Bogofilter as a "smarter" solution.
Basically, the filters in the panel are designed to handle very simple functions (and to do so in a fairly crude manner). They are not designed for general purpose content filtering... They will work for stuff like "delete email that is from this person" or "delete emails containing this specific string"...
2) Sort of. So far, we're not using any of the bayesian filter systems; our filters aren't "learning" from the messages, but unblocked messages are submitted to the master razor database. We do hope to implement further spam filtering solutions at some point.