The only trouble with being an early adopter in social media is … well, where to stop? While mainstream social media sites are down to a few big names – let’s say Twitter, Facebook, Foursquare, YouTube, LinkedIn and Flickr – it’s also entirely possible that, if you signed up for every new service that made it across Mashable and tried it out for a few weeks, you’d never leave the house, let alone sleep.

That said, if you have the foresight to be an early adopter on a service that makes it big, you’ve got the advantage of knowing how to make the most of it before your friends (or competitors) do – as well as grab that sweet username before someone else gets to it. (I managed facebook.com/jessicaschilling before the film director, photographer or former reality TV star got there, but was narrowly beat to the punch by @jessica on Twitter. Instead, I’m @dzesika, which is impossible to explain, let alone spell. Long story.)

Here’s some of the new stuff we’ve been playing with the last few weeks:

1. Quora. OK, maybe not brand new, but Quora has certainly been flagged as the Next Big Thing. If you haven’t heard word of one of your friends signing up for this question-and-answer service lately, you probably haven’t checked your email or even been on Facebook or Twitter. If you took standard social media navigation and interaction concepts and applied them to MetaFilter (which has been around since 1999), you’d have Quora, which really is a great concept; you align yourself with topics you consider yourself knowledgeable about, then watch the questions fly by and dip in when you want to contribute or rate an answer. Or approach it from the other side by asking a question and letting the experts pick it apart. But as everybody and their dog gets on Quora, it’s become increasingly disorganized and exponentially sillier. Example: The top question on my Quora home page upon logging in just now is “Which animal has been used most frequently for a band name?” To cope with the influx of new users and their burning need to know about animal bands, Quora’s working on algorithms to cut through the noise and rank user quality. In the meantime, we’re enjoying the melee, or at least enjoying watching people try to figure out what the heck to do with it.

2. Hipster. See “what the heck to do with it,” above – no one knows what Hipster is about other than the phrase it offers on its otherwise blank home page: “Something cool’s coming to (insert nearest major city to your IP address here).” Google searches don’t reveal too much other than some cryptic comments from its founder and some (no longer valid) results for what looks like a glorified city search site. Just to be ornery, we looked it up on Quora, and sure enough: “What is Hipster?” Again no real answer, aside from another “can’t say much about this” from CEO Doug Ludlow. Watch this space. (And if you want to give it a whirl, you could always vote us up for early access by using this referring link.)

3. One True Fan. It’s like Foursquare for Web sites – you install the One True Fan browser extension, it tracks where you’re visiting and “checks you in” to those sites in a quest to rack up the most points and become, yes, the One True Fan for your favorite Web hangouts. One can only imagine the sort of user behavior data this is accumulating – which could be worth its weight in gold to the right folks – but it’s also strangely compelling; even if you think you don’t really care about being the One True Fan of your work’s Web site (an entire newspaper, after all!) you get just a little upset when you’re ousted. Hypothetically speaking, of course.

What’s your favorite new social media gadget? Let us know in the comments below so we can play with it, too.