Screen shot 2010 12 08 at 11.52.38 AM 260x216 SimilarGroup: Find similar sites with this handy Blekko style extensionSurely you’ve used Blekko by now. The search engine, announced only a few short weeks ago, attempts to narrow down search even further than ever before by adding slashes that change the behavior of the engine. One of these, if you’ve not found it yet, is /similar, a function developed by SimilarGroup of Israel. That slash can help you to find sites that are similar in content to the one that you’re presently viewing.

While that similar feature is simple, we here at TNW are finding it hugely effective to gather all of the relevant information about a story. Of course, you can do it on a constant basis by selecting the Similar function in your Blekko preferences, but there’s also another way — Firefox and Chrome extensions.

Screen shot 2010 12 08 at 11.17.56 AM 260x313 SimilarGroup: Find similar sites with this handy Blekko style extensionThe group, started in 2007, has mapped over 20 million sites so far. What you end up with is a really interesting way to delve a bit deeper into your browsing experience. For instance, while browsing Facebook, I can click the SimilarGroup extension and I’ll get more results as you can see on the left.

The results are non-invasive, give a great overview of other similar sites and save you from having to head over to Blekko or DuckDuckGo in order to do the search. Time saving extensions? We love those.

So how does it know if things are similar? It’s not just content. SimilarGroup takes a look at user ratings, browsing trends, tag analysis and even semantic analysis to make sure that it’s always providing you with relevant results. While Google does the same thing, the ability to find similar sites while you’re on another one speeds up the process considerably.