Looking at the discussion here so far, a lot of it has understandably been focused on regular users; not necessarily high rep users, but people who have essentially "committed" to the site in some way, and know a reasonable amount about it. Suggestions like fine-grained notification settings are great for those of us "in the know", but it's a pretty high-end feature.
That kind of user - while obviously important - probably accounts for a relatively small proportion of page views. In particular, I guess (and Jeff may have figures for this) that most page views don't come through the front page at all: they're straight from a search result.
This question is aimed at encouraging users to take a fresh browser which they aren't logged into, do a search which gets a Stack Overflow result (e.g. int c# downsides) and seeing what it would look like to a completely new user.
- Is the meaning of the information obvious to you?
- Is this a community you would want to join, if you didn't already know about it?
- Is the navigation, etc. obvious?
I haven't actually done the experiment myself yet (at least, not committing enough time to it to give a meaningful answer) but I may do so some time in the future. It's hard to forget everything we already know about Stack Overflow and any quirks it might have, but I think it's a worthwhile thing to try.