I started using it about a week or two ago after someone linked a post called "Augmenting Long-Term Memory"[0] in another thread here. I've been reviewing daily and have already noticed knowledge that I was beginning to forget feeling refreshed and more solidified. For example, I used to be very familiar with the oauth2 protocol after having to implement a compliant service a couple of years ago. But I realized that knowledge was beginning to slip. After "Ankifying" some of the parts of the protocol that I thought were most useful, I have a good grasp of it again.
Since then I also started going through the ActivityPub protocol and Ankifying that, too. I'd scanned it a couple of times before and started building an implementation for fun, but I feel like Anki helped me grasp it better. I also don't have to refer back to the doc as much as I used to. Aside from the reviewing itself being useful, writing the actual cards has been very useful as well (but I kind of expected that, since writing/blogging has long been my preferred way of reinforcing new learnings).
I've Ankified different kinds of things so far, all in one deck. From details of auth flows to git commands (so I no longer have to Google each time I need to remember how to delete a remote tag or reset a git author).