Why not create periodic dumps of the database and allow people to glean interesting statistical data from it? You could remove any non-public information (passwords, preferences, individual up/down voting, last 2 octets of the IP, etc). It would be interesting to see what hours and what days people are active, where the visitors are coming from, what the most common words used are, etc.
The data you can gather from crawling the site aren't as specific as the data in the database. For example - you don't know the exact submission times of older pieces, only the day.