I've received a mail from Rapleaf few weeks ago with the following content:

Early in 2011, we decided to offer age and gender data, FOR FREE. You said to yourself, ‘these Rapleaf guys, they are loco, but hey, sign me up!’14 months, 30 billion free data points, and 15 billion personalized interactions later… The time has come to say farewell to free data. Thus, we are no longer offering free data as of 3/31/2012.The good news: please continue to enjoy data on the house, for the next 1+ month. New price: $0.005 per data point, per match. To ballpark cost, that's about $600 for age and gender on 100,000 email addresses. Not too bad, right?! The scoop: the plan was to offer these data points for free, on a limited basis, for a 3-month period. We kept pushing the free trial end date back, and back, and back… Call us too nice. It's been a great ride, and we had a terrific time working with all of you. Here's to more good times in the future.Currently our extension queries only the free data provided by Rapleaf and since there won't be anymore free data

Because of those changes I've decided to discontinue the development of the extension as of 31 of March. If we have enough inquiries to support the paid Rapleaf API, then we might change our mind.