I ran the reputation script and noticed that I would somehow gain 160 points in a rep recalc. While I used to be the king of downvotes until Evan knocked me off the hill, this still seemed like a lot of questions deleted to make that big of a difference.
So I started going through all the deleted questions, and was amazed at what was being deleted. A lot of posts that are outdated, but were relevant at the the time.
In other words, we're losing history, and I don't see any reason to be doing this.
One example is Kyle's post on StackExchange (can only be seen by 10ks), which he deleted himself on May 4, but this post had great information at the time, that is good history, and I wish he hadn't. Maybe instead of deletion, we should have some way of putting things in an historical archive.
I'm open for ideas.