A little background about me. I work in a Internet firm, we sell membership to our users for accessing our information service. (No, we are not in adult business, we are in financial service business) We have about four thousand paid users now. We also let user try our service for a month free. There are many “repeating” free users. They register for a month and then next month they register with another email. We know this and we don’t require a credit card in sign up process and we let them getting away for using our service for free for very very log time.

What they don’t know is that we only display Adsense ads when the free user logged in. For paid user, we don’t display any Adsense Ads. Paid users are getting more information and fast service. But this is not what this post about. This post is about our Adsense income. We saw our income steadily going down in past few months.

We had some discussion about this and we conclude that Ad-block of Firefox block our Adsense ad is the reason. Our site have been promoting FF for a long time. All our developers use a iBook. We all hate IE. About 45% of our users, includeing free users, use FF. More and more of them are turning on the ABP. I guess if our Adsense income going down too much, We will have to ask free user sign up with a credit card.