They've shutdown any interesting projects like pipes, maps, search or any other area of innovation. Anything that's still around is just rotting on the outskirts of internet. When was the last time anyone heard of YUI? The Yahoo! email experience is quite terrible and buggy with frequent service outages. They're purchasing these random startups and generally show lack of any direction. It just seems like their execs get in the room together and go "What the fuck are we gonna do today, boys? Let's buy a fashion startup! Do we need it? No, but who gives a shit. Our users sure don't." And I genuinely think that most users don't. They're just stuck on Yahoo! because they don't know how to change their default homepage.
I don't know... I'm just glad they haven't killed Flickr yet and I have a place to follow some great photographers.