Halfway because it is fast, but it's fast because it keeps the index entirely within RAM and thus you can't yet throw an arbitrarily-large disk of stuff at it to content-index.
If you select Search > Advanced from the menu, you get a window where you can enter the content to search for. This is available in the normal as well as the alpha version.
Halfway because it is fast, but it's fast because it keeps the index entirely within RAM and thus you can't yet throw an arbitrarily-large disk of stuff at it to content-index.