The signs now point to a bug in Microsoft's Internet Internet Explorer 6 SP1. You can read about the problem here.

Non-IE 6 users are also being impacted, however, because IE 6 users disrupt our web servers when they hit the servers. This short-lived disruption can result in non-IE 6 users seeing the same problem. Other websites are also being affected by this problem, although perhaps not as dramatically.

Therefore, if you are using IE 6, please go to the page linked to above (this one). Once there, you'll want to get the download listed under the RESOLUTION heading. After doing this, please let us know whether or not the problem persists. Those of us here with Internet Explorer 6 will download the patch in order to make the same observations.

Again, at this point, all of our tests have shown that the problems do not stem from our software. That noted, we are continuing to investigate the problem and to look for the best solution. We'd like to make the solution as easy as possible for everyone.