Why did Yahoo! buy Delicious in the first place? I assumed Yahoo! would use Delicious' links and tags to cleverly augment their search engine ranking. I realize now that I was giving Yahoo! too much credit.
The original idea was just that. But Yahoo! doesn't have direction. Even if they had a CEO, the company was just not focused enough on anything. First they said they wanted to be a search engine, then they moved to content and search...
Now they don't even have a search engine now, they use bing. They say they are a content and media company, but I don't really use any of their services other than delicious and sometimes the email, and I don't know anybody who does.
I think when they bought Delicious, it was a great idea because the company had direction and Delicious made sense. Over the years they lost focus, and have been just wandering around. They don't make sense.