There's some confusion about whether we support IE6 and IE7, and what it means in concrete terms if we do or if we don't.
It would be good to agree explicitly on what it means if we "support" a browser version, what it means if we don't "support" a browser version, and agree on a timetable for when these transitions happen.
Note that if we use a graduated definition of "support" (e.g. "core functionality will work in IE8 but not look as nice or miss a few addition features") then we should probably be explicit about that and timetable when that transitions to full on "unsupported" in the sense of, "it won't work" or "we'll actively prevent you logging in with that browser to prevent you having a poor experience of our software".
This was sparked by the presence of hundreds of lines of CSS that are there only for the benefit of IE6 and IE7 users. There were also some webkit and moz prefixes that are only needed for old versions of those browsers, which is a similar issue.