Since the regime change at Twitter there’s been a steady of stream of folks trying out Mastodon as an alternative. Mastodon is Twitter-like but is also very much its own platform, consisting of a federation of interlinked ‘instances’. As a newbie you select and join an ‘instance’, which makes a difference as to what posts (‘toots’) are viewed (there are 3 levels of viewing posts: home, posts by people you follow; local, posts by people in your instance; federated, posts from across the whole network that have link with your instance). Toots appear in chronological order rather than being sorted by algorithm. The instance someone belongs to is identifiable by their username and address (in my case @mastodon.social). See the Mastodon quick set guide for more info.
Within a couple of days of setting up I was following a couple of hundred folks and had a similar number of followers, many of whom I knew from Twitter. Quite a few of these are geographers, though I’m sure there are many more than this list, which is designed to help folk find each other and start conversations. You can also do that by joining the @email@example.com group and tag your posts with group handle to share there. Also tag your posts with the #geography hashtag. My top tip: having a bio and posting builds your community.
The list is replicated at https://lejun.codeberg.page/Mastodon-Geography/ maintained by @JauneBaguette@framapiaf.org and @firstname.lastname@example.org This version allows bulk selection of who to follow (with instructions). To be added to the list ask by tagging me in a post or by following.