Back in late March of this year, I reported at SEW Blog Yahoo Removed Block Result Feature From My Web. At that time, we did not have official word on Yahoo! removing the feature. Today, I spotted a WebmasterWorld thread that noted the Yahoo My Web FAQ had a new question named What happened to the block feature that enabled me to block any site from showing in my search results?
We have removed this feature from My Web. Previous users of the block feature can still access their blocked sites by clicking the Blocked Pages link under Go To in the My Web management Pages or Tags tabs.
So why has Yahoo! removed this feature from My Web? That is where the forum discussion comes in. Pure speculation, but some are saying that blackhat SEOs have made that feature unusable. I am not sure about that... The theory is that some how, blackhats blocked results of other My Web users, so that the results that go to the top, are their own sites. But that requires username and password of the searcher's Yahoo! ID. No? Maybe the feature wasn't being used and there was a lot of overhead?
The thread does state an inaccuracy. The thread creator says, "Google was anticipating doing something similar." Google has done something similar, they call it remove result and it is still active at Google.
Forum discussion at WebmasterWorld.