Lijit is about you and your friends who trust you enough to search any information over web posted by you as they say –
Using the power of people, their content, and their connections, Lijit enhances the way your readers search for and discover information on the internet. You serve as a filter for all of the results your readers could possibly receive, ensuring they only receive the most relevant results from the source they trust YOU.
You can add all your presence over Web 2.0 websites at one place and then let your friend search all that stuff which also include things like your blogrolls. It happens to be advanced version of Google Custom Search engine.
You are provided with a widget to be included in your blog where your visitors can search. A nice tool if you are really concerned about visitor search or SEO.