The obvious crap cluttering the front page is one thing. It's usually cleaned up within a few hours, and, while annoying, is relatively easy to avoid.
What's got my shorts in a knot today are all the old threads getting dug up by spammers. You read through what seems like a legit thread, then realize that the question is several years old, and the only activity is sig pimps answering the OP even though they are long gone.
Usually, the spam post which dug up the thread is gone, which is a good thing. The side effect is that people are wasting time answering threads that are long dead.
On the front page, we currently show the thread title and the username of the member making the post. Maybe we could add the date the thread was started, as well?
On a side note, have the rules against self promotion been loosened? Seems I'm seeing a lot more "PM me", "see my sig" and "see my site [link]" posts than I have in the past.