For a monthly subscription, you can have access to Levine's cellar tracking software. I have not reached the point where I feel that I need to document and track everything I have in my makeshift crawl space "cellar," but I have found the Cellar Tracker website to be useful nonetheless. The search engine provides free access to any wine that any member has ever written a note about and I would challenge anybody to try to query a wine that is not in the database. If you do find one, well fine, but the wonderful thing about finding a wine that you are interested in is that you have the opportunity to see what other wine drinkers have to say about it. Of course all of the posts must be taken with a grain of salt as each person has their own taste, but the notes can be used in a number of ways. Perhaps you were wondering if you would like to invest in a certain wine, or you heard that a particular wine might be just the special thing you were looking for for a special occasion, but you are not sure if you want to spend the money; well, on Cellar Tracker you would have the opportunity to read the tasting notes of however many people may have written about that particular wine and perhaps come to a concensus based on the multiple opinions that you had the chance to read. Another way to use the notes is to maybe come to a decision as to whether or not a bottle is ready to drink or if you should hold it a little longer. Also, a useful tool that can be accessed through the search engine is a wine shopping tool called Wine Searcher ; under each tasting note is a link that connects you to a long list of places that are offering the wine in question sorted from the least expensive to the most expensive.
I am sure that there are a myriad of ways that this site could be used that I have not even begun to tap into; take a look yourself and see how you might be able to use it. Cheers to Eric Levine for finding a way to make a living at what he loves.