The faster engine allows users to search for posts in real time by title, text and author's username. IndexTank also enables Reddit users to limit their searches to self-posts and specific "subreddits", but comments to posts are not searchable at this time.
Earlier in the week, Reddit announced its new premium membership service, and the site's improved search functions will certainly be a strong selling point for Reddit Gold. Reddit is similar to social news aggregation site Digg, and claims about 8 million unique monthly visitors per month.