[imp] What does "Report as spam" do?

[Rob Brandt]

Nuts & bolts question:

What exactly happens when the "Report as Spam" link is clicked?  I've always
assumed that this is a tie-in to spamassassin's bayesian analysis features, and
at times I've personally used it to report spam, but it doesn't seem to make
much difference.

Is it for spamassassin?

If so, and someone wants to answer an off topic question, how can I tell if
spamassissin is configured correctly?  I'm using Postfix-courierIMAP with Mysql
authentication.  Spamassassin is invoked on a domain-by-domain basis using
maildrop as a transport, with spamassissin being called in one of the lines in
each user's maildrop filter.

Thanks

Rob