Here’s some internet stuff I really like. Given the breadth of knowledge I see from the commenters here, there’s a good chance you’ve heard of most of these. But maybe there’s one you haven’t.
HotSheet has been around since the Internet Jurassic. If your folders are sufficiently organized, you can efficiently use powerful links of many varities. I just use HotSheet as a multi-folder.
Likewise for comic book readers and ComicsAlliance. They’ve got several really funny geeks chained up in there.
There are also many supernerds at io9. They will suck up to anything involving the imagination.
Guess there’s a lot more “fun” than “useful” here, huh? Well, Hot Sheet makes up for it.