Elon Musk is growing a social network. Just not the one he wants.

One of the biggest beneficiaries of billionaire Elon Musk’s chaotic ownership of Twitter is a small social network most people hadn’t heard of two months ago.

Mastodon, an alternative microblogging platform, has had several spikes in user sign-ups since Musk, the world’s second-wealthiest man, bought Twitter in late October. Hourly data from a Mastodon user counter shows that the surges typically happened shortly after some of Musk’s most headline-grabbing actions.

Mastodon-powered sites averaged about 130 new sign-ups an hour from Oct. 1 to Oct. 26. The number jumped to 2,000 an hour after Musk took control of Twitter on Oct. 28. Sign-ups rose to more than 5,000 an hour after Twitter began mass layoffs a week later, and they peaked at almost 10,000 an hour after employees resigned en masse following an email ultimatum Nov. 17.

New sign-ups spiked again in mid-December, when Twitter suspended journalists who had been reporting on Musk and the company, and again when Twitter abruptly banned users from sharing links to their profiles on other major social networks.

Since Musk’s takeover of Twitter, journalists, news organizations, authors and politicians have created Mastodon accounts. But Mastodon, which is open-source and built on a model of hundreds of small sites that talk to one another instead of one large site, is still very small.

There were about 8.7 million users across Mastodon-powered sites tracked by instance tracker Instances.social as of Wednesday. Twitter, which reported 237 million users in the second quarter of 2022, is 29 times larger. Facebook, with 2.9 billion users in the third quarter of 2022, is more than 300 times larger.