Facebook users wanting to post links to another social media site will find their comment blocked, it has emerged.
When people try to add a link to Tsu.co, which is a small invite-only social network, Facebook blocks the post and does not let it appear.
Even mentioning it in private on Facebook Messenger will not work, and earlier posts including links to Tsu have been deleted, CNN has reported.
Yet this is apparently not an aggressive competitive strategy but an effort by Facebook to prevent "spammy behaviour," according to Mashable.
Facebook said that sites like Tsu violate its rules on spamming, which is defined by the social media firm as "sending bulk messages, excessively posting links ... and sending friend requests to people you don't know personally."
A Facebook spokesperson told Mashable: "We require all websites and apps that integrate with Facebook to follow our Platform Policy.
We do not allow developers to incentivize content sharing on our platform because it encourages spammy sharing and creates a bad experience for people on Facebook."