Searching forums for specific posts can seriously suck. Most have proprietary search tools that can be unfamiliar or downright difficult to use. Some even require you to fill out a captcha to avoid getting attacked by bots or having its forums infested with spam. Twing is a new service that's attempting to solve these problems with a search tool that scours hundreds of user forums and lets you search by individual posts or a topic thread all in one place.
I found it to do a pretty good job giving me some basic results with simple queries. You can also filter down your results with a myriad of tweaks, right down to what type of forum content you're looking for, be it audio, video, or images. These filters and special terms can be stacked on top of one another, letting you hone your search a little or a lot depending on how much effort you put in. I found I was able to get a general list of posts that had something to do with what I was searching for with a fairly minimal amount of effort--which is a good thing.
In addition to a search, there's an entire directory of forums listed alphabetically or by interest. This is actually one of the coolest facets of the site, as it will tell you how many posts and users a forum has, along with its growth (presumably within the past 30 days). It's a great way to see what's hot, regardless of what forum platform it's on.
What wasn't working when I tried out Twing earlier today was a neat little info button that expands below each search result. I'm assuming it gives you a quick overview about the forum the post is in, but it was coming up blank. Presumably when it's working, you can see whether the forum you're about to view the post on is populated with a large audience and a lot of topics, or just small with good SEO.