The Google Video Blog announced that they have added two new search features. The first feature is to allow you to sort a search query by user ratings. The second feature allows you to search by keyword and append a label (tag) you want to filter that search by.
An example of sorting by rating is if you search on anything, and then by default Google "sorts by relevance." But you can click on that sort option and change it to "by date" or "by rating."
An example of searching a keyword and filtering by label would be label:basketball jordan but for some reason only one result comes up, I have tried others like label:basketball bryant and nothing comes up. Google's example is for label:soccer zidane and that, of course, works nicely.
Postscript: I know see that only 4 videos are labeled with basketball so that is why the results I listed above are disappointing.