When I decided to ditch WordPress for my blog here and start playing with other blogging engines, one of the things I wanted to make sure of was that content could live on no matter what platform I was using. I don't subscribe to a complete archivist point of view where every URL that ever lived has to live on for eternity (it's a noble vision mind you, just one I don't find all that realistic) but I do my best. I've switched the software on this site on 3 different occasions moving from WordPress to Anchor to Ghost which is the platform I use currently. Anchor didn't offer a migration strategy for content so I kept my old WP site humming for old posts but when I moved to Ghost I wanted to consolidate everything here.
Awhile back I had decided to switch from WordPress's built-in commenting in favor of using Disqus. I liked the features it offered and it seemed just as good as anything else (and if there's any theme you'll find on this blog it's that I just like playing with stuff). I didn't know at the time how important it would be for migrating content between platforms. Anchor had a built-in mechanism for comments as well but I never used it and opted to throw my Disqus embeds there as well. With the final move to Ghost which had no commenting system at all it just made sense, and that's where the idea of having a portable commenting system became really powerful.
Disqus has the big downside of course in that it's a company and while I can use this open source software Ghost as long as I want, the same won't be true for Disqus. But they have a variety of tools at your disposal including export options so I'm confident I can always move on to something else in the future. For now it's great that I can drop a commenting system in place and keep rolling regardless of whether the software I'm using has support for comments natively. It's also been nice to not have to worry about spam without a handful of plugins (hint hint WordPress). Integration isn't too hard, they provide some basic code and if you have a good-enough understanding of how your CMS handles URLs and post IDs you can figure out how to setup the embed code for custom platforms as well.
I'm sure at some point Disqus will get bought out by some large company, rolled into their feature set, and disappear as a free service. But for now it's a great tool for adding comment options and it's given me freedom to migrate platforms here with relative ease which is worthy of praise.