Happy Friday @kfitz! You’re in luck—its not even horizon we’re watching for, but new lands we can walk. There are several options with varying levels of technicality and user interface affordances:
POSSE
There are some well built and not overly complicated pathways that allow syndicating from your WordPress website to a Mastodon instance and getting responses back from them, just as I think you’ve done with Twitter in the past. Most of these can be done with plugins like Syndication Links or Mastodon Autopost or a handful of other similar plugins in conjunction with Brid.gy (which does the work for bringing back responses). Personally, I prefer Syndication Links for this and it particularly dovetails well with other IndieWeb infrastructure like Micropub clients.
Mirroring
There are a small handful of methods for “mirroring” your WordPress site so that it will look like its own (single or multi-user depending on your configuration) instance within the Fediverse running ActivityPub, meaning that those on Mastodon or other related platforms could follow your site directly. Most of them are configured as publishing only, so you won’t have a built in reader interface and would have to rely on other (available) infrastructure for those portions.
Option 1
(More technical, and with a few less features) Brid.gyFed, which has options to do the syndication to a separate instance mentioned above, as well as making it look like your website appear to support ActivityPub.
More details on this here: https://indieweb.org/Bridgy_Fed
Option 2
Our friend Matthias Pfefferle, a genius engineer and longtime opensource advocate and WordPress developer who has also written significant pieces of other IndieWeb code you’re already using on WordPress, has written a handful of plugins which will make it appear as if your WordPress site supports ActivityPub out of the box. You’ll broadly want the following plugins: ActivityPub plugin, WebFinger plugin, NodeInfo(2) plugin.
They don’t have very many configurable options though some may be hiding a bit, so try:

/wp-admin/options-general.php?page=activitypubwill give you options for how your posts appear;
/wp-admin/users.php?page=activitypub-followers-list will show you who is following your site so you can more easily subscribe back via a reader if you like;
/wp-admin/profile.php and look under “Fediverse” where your profile identifier will be found. It is based on your username within WordPress.

The documentation for these plugins are scant and I’ve got the intention to write up something explaining the subtleties and a few quirks, but it will have to wait until the holidays I’m afraid. In the interim, they’re not as complete as they could be, but the following two blogposts have some useful details and hints, though its obvious to me that they’re much newer in the space:

https://odd.blog/2022/11/06/how-to-add-your-blog-to-mastodon/
https://g13g.blog/2021/03/16/get-your-blog-posts-on-mastodon/

There are one or two quirks still pending for how things display if you’re using the IndieWeb-based Post Kinds Plugin, but the developers are generally aware of most of them and will hopefully get them ironed our shortly.
As a result, mostly of these plugins, WordPress is already the fifth largest number of instances in the Fediverse with an (under-)estimated 878 as of this morning.
I’m practicing both the POSSE option as well as Option 2 above on my own site, which can be followed at @chrisaldrich, as an example. Matthias’s example can be found at @pfefferle.
Help & Questions
This is a lot to consume and potentially implement, so, as ever, I’m happy to help guide and lay out the sub-branching options or even hop on a call to walk through bits with folks who have questions. David Shanske and I have been thinking about doing some group sessions and some training videos to walk people through some of this within the next few weeks. There’s also the IndieWeb chat which welcomes questions and conversation which is sure to give you some additional perspective: https://chat.indieweb.org/wordpress/.
For the social reader portions I briefly mentioned, I outline some of those options last year at OERxDomains in A Twitter of Our Own.
HCommons
Separately, congratulations to HCommons having stood up a Mastodon server so quickly!
It looks like it’s running Hometown, which has local only (unfederated) posting, though I’m not sure how many are aware of that useful feature (hiding on the link in the posting interface) which is sadly missing from most Mastodon instances, particularly for smaller communities. It might be something useful to add to the welcome email? I think this could be a great feature for Universities to allow more private class-based social networking while providing some safer spaces that don’t reach the broader internet and which might comply with FERPA. Obviously it would need some testing and some of the barriers for standing up and maintaining these servers to come down a bit.
There’s a lot of messaging and potential education to be had to roll it out well, but it could be interesting to see the WordPress offerings from hcommons.org include some of these IndieWeb and Fediverse tools as well.

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