This is SPAM.
I have a yahoo email account, Yahoo has started the "This is spam sweepstakes"
I've been using Yahoo's spam gaurds for a while now and found them very effective.
+1 for very effective. Some gets through, but nowhere near as much as gets caught, and it seems to get better over time.
I had a similar experience to the original post, however it was prior to the contest. It seemed to start when they introduced their newest version of spamguard.
I've seen the same thing: check the box for "enter sweepstakes", see your inbox spam count rise for the next day or so. But it's rather hard to prove any correlation, because the spam that gets through yahoo's filters always comes and goes in waves.
I'd participate in that promotion if they kicked people out for falsely blocking. What makes virtually every spam blocker unusable is that they have terrible records blocking legit emails.
I've had a few of those, thought I find them easy enough to handle.
Out of curiosity, I checked my Yahoo Mail box and found some 15-20 spam, even though I haven't clicked to participate in any contest.
I've seen the same increase when I was actively clicking the "This Is Spam" link on spam. When I stopped identifying spam for them, less spam started getting through.
I used to use the yahoo "this is spam" button to tag stuff that got to my inbox, and then a few months ago I stopped, and as far as I can tell, there has been no difference in the level of spam coming through to me.
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