It took me 15 minutes to understand what "feed" means, which then lead me to understand what "social service" means. I think you intro paragraph could be clarified by replacing the word "service" with "platform". I know this isn't strictly true, but it's clearer to distinguish between platforms, which are for developers and services, which are for users. Try this:

"We're building a real-time platform that allows developers to create social services where users come first, not advertisers.

Our team has spent the last 9 years building social services, developer platforms, mobile applications and more.

We believe that advertising-supported platforms are so consistently and inextricably at odds with the interests of users and developers that something must be done.

Help us create the platform we all wish existed."