The broadband video service Joost has been struggling to keep up with demand after extending its pre-launch testing by allowing trial users to send unlimited invitations to others.

The Joost service opened for business on 1 May, allowing existing Joost beta testers to invite an unlimited number of users to sign up. However, many users have found the service temporarily unusable as its central servers strained under the demand.

Although based on a peer-to-peer assisted network which should theoretically enable it to scale to a virtually unlimited number of users, the dependency on servers in its distributed data centres has resulted in problems under the load of new users.

Joost chief executive Fredrik de Wahl said in a statement that the system had been flooded with demand, which was ultimately good news as it would make the system stronger. “It’s stumbling a bit,” he said, “whereas we’d like it to be sprinting”.