If you wondered how often people actually ride Divvy bikes, everyone's Divvy online trip summary page has the answer. They put the trip ID right on the page. My first Divvy trip, on September 18th, was #522105; this morning's was #732089. Assuming they use an ID field that auto-increments by 1 for each ride, that means Divvy users rode about 210,000 times in the past 22 days, or about 9,500 times a day (on average). That rate gives them nearly 3.5 million rides over the next 12 months.
Compare that with the CTA's 314 million bus rides and 231 million train rides, though. The 79th Street bus had 10 million rides last year; the #36 bus (one of five that stop near my house) had 5.8 million; most of the 150-odd routes had over a million. So will Divvy actually eat into CTA ridership? Not for a while.
I'll look for more official sources of Divvy participation, especially on revenue.