First, turning to highlights for the quarter. Total membership grew 21% from the prior year to 731,000. Revenue increased 15% year-on-year to $70.8 million. Adjusted EBITDA grew 47% versus last year to $3.4 million, and our net loss was $422,000, an improvement from a loss of $5.6 million in the second quarter of last year.
Our adjusted EBITDA and U.S. GAAP net loss for the quarter were both within the range of the guidance we gave. However, while we reported solid double-digit gains in our top line performance, revenue growth was below our expectations due primarily to lower-than-expected new member additions during the quarter. We also saw slower-than-anticipated growth in the U.K., which is our second largest market.
Lower-than-anticipated new member additions in the period reflected softer returns on our marketing programs, most notably, around our first test of broadcast media launched in March. The campaign, which included both streaming and terrestrial radio, did not meet the objectives we established. For the remainder of 2012, we've eliminated radio from our marketing mix. We expect this change to drive down CPAs from the levels we incurred in the second quarter. We're also taking aggressive steps to reignite growth in new members for the coming quarters, and we have a number of new member acquisition initiatives in place.
First, we're amping up our referral program by making it easier for our newest numbers to refer Zipcar to their personal network. Second, we're opening up new partnership channels. Third, we're enhancing our social media efforts. Fourth, we're implementing enhanced online media tracking and attribution technology. And fifth, we're working to improve our process as related to performance management of our online display media campaigns.In addition to steps to improve returns on our marketing dollars, we're also evaluating ways to broaden our appeal by reducing barriers to trial and making initial access easier and more affordable. I'll touch on this initiative additionally in a few minutes. Read the rest of this transcript for free on seekingalpha.com