Apparently all of my old mail was purged because I don't use Yahoo that often.

I use Yahoo Fantasy on a semi-regular basis. So I thought I was still active with an active Yahoo account.

If that's indeed what happened, that my email got purged even though I was using Yahoo Fantasy, that's a pretty terrible policy and probably should be widely advertised on billboards and stuff. I lost years and years of email from a while ago that I didn't use as often but still referred to from time to time. Consider me a very dissatisfied user.