Although you have browser support covered on a doc-by-doc basis, I would find it useful to have a rollup page by browser of gotchas. e.g. all the common JS gotchas for IE8 (e.g. no go on client.innerWidth), IE9 not supported opacity, etc.

Here's a ghetto example of a reference file I started after recent project that drove me nuts which would give you the sense of what I mean: https://docs.google.com/spreadsheet/ccc?key=0ApBq5nqLSn9MdER...