Just came across an interesting web site that talks about how online companies track computers across the web.
It's worth a read to gain an understanding on how to purge your cookies (the ones in your web browser), and how to clear Flash cookies as well. This should be done at the end of every browsing session (even though it will force you to re-enter memorized, web site passwords each and every day.
I just installed Better Privacy as a Firefox add-on, which offers an easy way to manage Flash cookies from the Firefox privacy menu page. So far, it lives up to expectations.
I realize that real Inet privacy is a tough thing to accomplish, but every little bit helps when it comes to addressing this area.