1st time hearing on before but why they do that if then it will create problem for them when they try to showing result by search that's all
They are not completely sure about that, they still taking votes and marketing analysis about that, it may not close.
I am sure that yahoo is going to close mybloglog because I have got message from yahoo to take care of my account there. but I am not sure about delicious. I have searched for "is yahoo going to close delicious?" and the results are saying that yahoo is not going to close it but going to sell it. you can read this: http://www.socialtimes.com/2010/12/yahoo-isnt-going-to-shut-down-delicious-theyll-just-sell-it/
Officially they aren't shutting it down but trying to sell it. However, since nobody is interested in buying it (or yahoo have overvalued it's worth) then don't be surprised if it closes at some point or, more probably be merged with a similar site.
today I read a news on DP that yahoo almost sold Delicious for $5M, is it true ? any source to confirm that ?