When I left for choir practice this evening, I had 2 messages in my inbox. When I returned, I had over 600! Remember way back when I said that I removed that setting that left a copy of the e-mail on the server? Turns out in Ximian Evolution, “Close” is the equivalent of “Cancel” in most apps, and my change did not take. It looks like my ISP's mail server, in an effort to alert me that I was over my limit, started clearing whatever status was on these messages, which caused them to be downloaded multiple times, every 10 minutes. I made sure the setting was set, then went into my ISP's web mail service and deleted every message in my inbox. I deleted all the dupes out of my main inbox tonight, and I'll delete the dupes from the other folders tomorrow.