The search bar does search for tags. Putting in "vanilla" and hitting "Enter" produces the page for the tag "vanilla."
Everything works fine unless you enter "color." It seems that entering this specific word sends you to the "video search is not yet working" page.
People are free to try it and see what happens. Though I doubt it, it may somehow be the browser I'm using (Opera).
And like I said, it's not a big problem, but any bug, no matter how minor, should at least be brought up.