I joined Twitter on October 12, 2006 (only a few weeks after Facebook).

I joined Diaspora on October 12, 2011.

I joined Mastodon.social on October 7, 2016.

This October, to celebrate Elon Musk buying Twitter, I created another mastodon account on chaos.social, and intend to finally make the fediverse a regular part of my umwelt. UPDATE: I did.