I've stumbled across Digital Mappa a good long(ish) while ago, and I might or might not have posted about it here on the blog, but it might be time to revisit that.
Digital Mappa is a tool for digital annotation of manuscripts and images, with the possibility to link multiple different sources, highlight parts of them, and, in short, do a bunch of interesting and potentially helpful things when researching and comparing stuff. Back when I last looked into it, I didn't find anything where you could use the platform without using your own installation. Which I tried to set up, but failed.
A while ago I received a note about an update to the platform software, and I put on my list to check it out and maybe re-try installing it. These days, I finally got around to looking into it - and I found this article about DM. With, to my utter and great delight, a link to an installation where one can register and then use an already installed, up-and-running version.
Hooray! I've not spent a lot of time with the DM yet, and it certainly takes a little while to get used to, but I have hopes that it will be very, very useful for me and some of my projects - including some collaborative projects as well.