I know IE 7.0 is pretty old, but some companies are still using it. I haven't minded weirdness in tag layout, picture upload oddness or other nice-to-have-but-not-essential features, but I'd like to make a bid that this one is killer.
IE 7.0 doesn't show the links available in the tag with the id "top bar". Other parts of the page are fine, it's just the text in this bar. And it only happens after login - it was fine with an unlogged in user.
Unfortunately, that means that a couple of key things are ommitted - that includes - the user's data - including the "logout" tag - so you can't revert without scraping out your cookies - the meta - where the users would hopefully report a bug!!
Normally I'm cool with being stuck loosing some features on an old browser, but I don't think this is OK. Also - this isn't true on every Stack Exchange, and it wasn't true on IT Security until we got the new site design.
Please review the CSS and see if there's something in there that IE 7.0 can't handle.