Who is the leader in social search? The dead service, obviously.

This is not a comprehensive sample, so I'd like to hear your additions (or corrections) in the comments.

One common complaint about most social services is that they are heavily oriented toward people, but are not heavily oriented toward topics. For example, I may subscribe to my co-worker James H. because I respect his views on biometrics. But when I look at James' feed, he might be talking about Angry Birds. And heaven help anyone who looks at MY feeds to find out about a particular topic.

As I write this, the riots in London continue, and sadly have reached the point where they have their own hashtag.

So let's say that I want to see what my Google+ friends are saying about the London riots. After all, Google is the acknowledged prominent name in search, so Google+ should have some sort of built-in facility, right?

Not yet. Perhaps they're re-tooling Realtime to handle this, but it's not there yet.

So let's go to Facebook. Again, the leading social media outlet has no way to search through posts of friends, or your own posts.

Twitter, of course, does have search. After all, they bought Summize to get it. So I can type in https://twitter.com/#!/search/%23londonriot...and see what everyone is saying about #londonriot. If there's some way to see just what my friends are saying about the topic, it's not intuitive. One other drawback that (thankfully) doesn't apply to the riots - if you want to search tweets from a few months ago, you can't.

So what is my favorite social search capability? Now I'll be the first to admit that this search capability has been flaky in the past, but it has worked well lately. And you can even search the entries for your friends only, or your own entries only, or someone else's entries only. Here's the search that I used to see what my friends are saying about #londonriot:

http://friendfeed.com/search?q=%23londonriot&friends=empoprises

Yes, that's a FriendFeed search. You know, that service that died a couple of years ago. Yet this so-called dead service has better topic search than FriendFeed's former employers, and better topic search than it's new employers.

Question: is there any other social service who does a halfway decent job of search? If so, please mention them in the comments.