Some weeks ago a more or less large scandal popped up in the media: Cambridge Analytica misused data from Facebook. Many users of Facebook were unhappy about abusing their personal data and deleted their Facebook accounts - or at least tried some alternatives like Friendica, Hubzilla, Diaspora, Mastodon and others.

There has been a significant increase in user count since then and this gave a general boost for the networks.

Apropos networks... basically there are two large networks: The Federation (Diaspora, Socialhome) and The Fediverse (GNU Social, Mastodon, postActiv, Pleroma). Within the two networks all solution can exchange information like posts, comments, user information and such, or in other words: they federate with each other. So, when you use Mastodon your posts won't be available to Diaspora users and vice versa as they use different protocols for federation.