My Yahoo! mail account is acting pretty weird. Two things concern me.
The first happened a few monthes ago: A huge bulk of my (already read)
mail in the inbox disappeared. The second - I have no idea when it
happened, but I discovered it yesterday: a good 80% of my address
book, as well as others, whom I wouldn't mind receiving mails from,
were in my "block mail" rubric. On the other hand, those who were
there and were mostly repeating spammers, disappeared!

What happened? 

Warning: This question is intended to Webadept-ga and to him only. If
other researchers (or commentators) may have a solution or
explanation, they are more than welcomed to leave a comment. If
Webadept cannot (or will not) answer it, I prefer to close it.