Divvy has put up a station suggestion map.  Letting Divvy know where users would like to see more stations is great to make sure that important gaps are closed.  

I personally would love to see more L and metra stations have a Divvy station nearby. This lets people connect between public transit and their destinations without making often awkward bus transfers.  Its one of my main Divvy uses, since I dislike bringing my bike on board, or locking up at stations since most have high theft rates. 

http://suggest.divvybikes.com/page/about