compound meanings through terms and clusters

There are great sites that help to pre-chew a lot of information for you somewhat — search results are sorted by relevance, news feeds are combined into one list by date, tags combine like photos into one page. This is a huge improvement that people are only starting to usefully take advantage of.
But actually taking things a step further with these sites is a pretty manual process: I save a few items, follow some links, email a few, post some to my bottomless pit of a bookmark site. I can connect to information one application at a time, and I never see the big picture. The words I search for or tag with are my own, but they are spread all over a bunch of separate applications. I don’t do a good job of tagging, I am not great at formulating a search query, and I couldn’t put into words the topics I want to read about.
I would like some way to combine and compound the words, meanings, and content in these separate applications. The words that I use to search for something are the same words I use as tags, after all. But now they are in separate meaning-silos. A useful compound relationship between these sites would help me understand the words I use better.
In fact, a means to do this already exists, clustering, but it is not used as an interface to information right now. Creating “clusters” of terms means showing the groups of ways that people commonly understand a word: for example, “jaguar” can be a car, or a cat, and grouping around either car or cat could work across applications (search, photos, news) and content types (search results, articles, photos). You can see this for yourself on Flickr cluster pages for jaguar, java, or San Jose.
And clusters are derived from the ways that people use content, so they can show me how a word I use (“java”) is understood generally (a programming language, an island, or a kind of coffee), and give me a direct line to improving my understanding of the concept (e.g. many of the people who use the word java in the Indonesia way are interested in Borobudur and yogyakarta, so I should look those up if I am planning a trip there). Seeing clusters helps me better understand my own ideas and words, and creates a compound of my own words and meanings and those from the outside world.
I believe that an interface that would connect the words I use with the words the rest of the world uses, through clusters of content, could be very useful.