logicmaze - 2:06 pm on Sep 29, 2006 (gmt 0) I could be wrong, it has happened before(one time, back in 1998!)
We run analytics on 77 clients sites and we have a ton of yahoo mail refererrals! Especially on Yahoo stores, it's a big community. Yahooers are fanatics and love to communicate with others of their kind. I think it is probably as simple as I stated before, one Yahooer finds the site or finds something new/interesting and emails a link. For those of you who just set up a Yahoo PPC campaign and started getting Yahoo mail references could it be possible that the CSR at Yahoo handling the account liked (or disliked!?!?) Your site and sent it around the office. Hate to be the simple minded one here but I think that is more often than not the case.
I could be wrong, it has happened before(one time, back in 1998!)