#8 - May 11, 2007, 7:43 p.m.
The background downloader will grab bits of upcoming patches before they're officially released so that on patch day you only have to download a remaining megabyte or so, patch, and then you're able to log in pretty quickly. It's been a normal part of the patch downloading process for quite a few patches now, and it should have gone active yesterday I believe to start downloading part of the 2.1 patch. Actually the bulk of it more than likely as I don't believe it's too much larger than 250MB.