Youlicit is a new tool that helps you "Search less and find more". Often we forget that search is only one means to find what we are looking for. Even search by itself is not the endpoint of an information need or a query. This tool reminds me of the "berry picking model" of Information Retrieval that I had read about first in my IR Class. The model basically says that:
Information need is not satisfied by a single set of documents but by bits and pieces found along the way.
The paper titled "The Design of Browsing and Berrypciking Technique for Online Search Interface" describes a searcher as
Moving through many actions towards a general goal of satisfactory completion of research related to an information need.
What Youlicit does is provide this ability implicitly, without the reader (or more generally a searcher) having to go through the trouble of navigating and mentally processing through hyperlinks or firing search queries to find related content. Youlicit takes care of all that on your behalf. By providing a simple plugin, the Youlicit widget automatically highlights some of the related, relevant links and provides useful suggestions -- all without your audience ever leaving your blog. I love the idea and the neat implementation that these guys have built. (The very same need was what lead me to hack this Wikipedia related widget a few weeks earlier.)
On the Youlicit site, you have lots more interesting tools. You can discover new content that is relevant to your interests, find related users and share links with them or follow their interests. Youlicit is paving the way for social browsing tools and is a neat concept that is well implemented. Their index does not seem to be very large at the moment and I feel that it would get better as they start to seriously scale up. In the interim, I feel that there might be stopgap solutions that they could be employ -- for example the Alexa related URLs for the links that are not currently in Youlicit's index.
In relation to this plugin, one tool that is similar is the Sphere plugin that shows related blog posts. I feel that sphere serves a complementary need. From what I understand Youlicit aims to find the interesting blogs and Web URLs one might want to look into in relation to a given hyperlink.
Another plugin is the Snap plugin -- which shows a screenshot of the outlink. However, in my opinion snap does not really serve much purpose and is a bad tool from a usability perspective.
Youlicit is non-intrusive and you are gonna enjoy the serendipity of finding interesting new links! Give it a spin!