I've had several times where I'm testing a site in IE6, find a bug or quirk, then press Ctrl-N to open a new IE6 window, and browse to W3C (or other web development related site) to find a reference to that particular element and determine its compatibility with the browser I'm currently in. I'd say that's pretty common.
Ben174 writes: "I've banked at a couple different banks and haven't yet been able to find one that offers the features I need. I'd like to find a bank that supports open standards, such exporting my statement data to a XML file format. I'd also like to write scripts to monitor my account and send me emails when my balance reaches X, or if a transaction occurs within X miles from my zip code. Do any banks currently support this?"