There are suddenly a lot of real-time search engines around the Web now. Most of them are aimed towards social media like Twitter and Facebook. While Google has a definite disadvantage in this arena, these little startups are hoping to edge in by exploiting that to become the next big thing.

Some are content aggregators, pulling RSS feeds from blogs and news sites in near real-time. Others are aimed at the APIs of the most popular social sites out there and can show an auto-updating display at close to real time.

Most Twitter-specific search engines, for instance, are geared towards the popular hash tags (#FAIL and #Iranelections) as their search criteria or the basis for their existence.

Really useful search tools, however, are not nearly as common as some of the startups banged together by developers and generally meant for their own use. What we’re focused on here are the search apps that produce real-time results on broader categories or user-specified search criteria.

Almost.at – This site gives a 3-part page of results: a live stream, shared links, and photos. It’s aimed specifically at event bloggers and tweeters, which explains the results. So if you’re watching the upcoming vehicle show in Iowa, you can search for it here and see live results from those tweeting from the event and see shared links and photos from those blogging it too. It pulls from Twitter, YouTube, and Flickr. Great, focused results for a good niche.

Collecta – This is a brand new site that claims to be the fastest of the real-time search engines. It pulls from the Web at large, so it made our list as at least being one of the more useful. Irrelevant results are common, however, so consider this the real-time version of Google rather than a specific engine.

OneRiot – This one focuses entirely on the content being shared (links) and pulls from both Twitter and Digg to get those results. So the more often people are tweeting and the higher the number of Diggs for the content, the higher it’ll be ranked. Tweeted Diggs have an obvious advantage here. It’s fast and gives pretty relevant results for most searches.

Scoopler – This site gives results in two columns on the page. One side is live content that’s unfiltered and the other side is sorted by popularity. So if you’re search is for “#rev2” you’ll see relevant, but unfiltered, live results on one side and returns sorted by how often they’re RT’d or posted on the other. It’s a useful, fairly fast site that does what it says, polling Digg, Delicious, Flickr, Identica, and Twitter.

Topsy – This one is Twitter-only and weighs results by popularity, timing, and the source. So results will be ranked according to a score derived from who sent it (and their “influence”), how often the tweet (or link) is being shared, and how recently the content was posted last. Influence of users is measured by what percentage of their tweets are RT’d and responded to. The site is fast.

TweepSearch – This is a username/profile search engine for Twitter. It crawls user bios and accounts for data and brings results based on your search. Searching for a name, however, doesn’t always work since most users don’t attach their name to their account. It cannot hunt by email address either. So it is only useful if your target uses their real name or their username is already known (or partially known).

Tweeexchange – This is a product that was made on VOIS and is geared towards finding or offering Twitter usernames to the market. It’s also very useful as a live engine to check for username availability.  The results are dynamic, as you type them, with links to Twitter for each result.

Tweetibird – This has to be the fastest Twitter search engine available now. It’s brand new, but pulls a constant stream from the Twitterverse and gives very fast, consistent results. Even heavily-trafficked searches like “#Iranelections” will be returned with fast, streaming results. Very nicely done.  Almost looks too much like Twitter.  Wouldn’t be surprised to see them hit with a Cease and Desist.

Tweetmeme – If you know what a meme is, you understand the concept behind this popular Twitter search site. It displays the most relevant and most-often tweeted content on Twitter and ranks it. Searches will show your item narrowed by those criteria. Very popular Twitter portal.

Of course, Facebook, Friendfeed, Twitter, etc all have their own search engines built-in internally that you can use as well. They tend to be relatively limited and not as useful as some of these alternatives, though. Which is exactly why these exist.

Do you have a favorite that wasn’t listed here? I skipped quite a few in the name of time and space limitations, but if you’ve got one you’d like to mention, feel free to do it in the comments below.