What gotchas are there for existing sites to render properly in Internet Explorer 8?

Question

Now that IE8 is out, what are the gotchas that web developers are likely to encounter in their existing sites? Is there a list of "breaking" changes? Or is this thing "just going to work" with existing sites?

Answer 1

There are some great reference pages over on www.quirksmode.org. This site keeps a detailed record of the features supported by all major browsers, including IE8.

http://www.quirksmode.org/compatibility.html