I've had the domain for about 12 years - never dropped. . No complicated redirects.
Something in the back of my mind tells me that Yahoo emailed me back around 2002 or so saying that if I didn't pay for their paid search inclusion, they would permanently remove me from the index. Or something like that. I remember thinking at the time it is such a rip off and so I didn't pay.
Consequently, I am wondering if that has something to do with it.
[edited by: martinibuster at 7:18 pm (utc) on Feb 8, 2010] [edit reason] Removed URL. [/edit]