From the description it could well be a justified speedup to look for. People tend to have knee-jerk responses, and sometimes those responses are inappropriate. With 500,000 users on the system, scanning it each time could quickly become prohibitive.

About being back. I also like being back. Interacting here forces me to constantly rethink what I think I know, and exposes me to things that I didn't know. This is very valuable for me. (Not to mention fun!) Plus there are all of the people I know and enjoy talking to...