I have (had) a Disqus account that I connected to via my google account. I say had because I haven't been able to login in a year or so via firefox. I just get a page that says "There was an error submitting the form. If you're having difficulty, try repeating the action on https://disqus.com" with an annoying meme gift on the background. Luckily the title of the page says "Embed: CSRF verification failed (403)" but I have not been able to find a way to fix it. Oh well, I guess I won't be commenting on any site with disqus anytime soon.

I wish there was some kind of service or plugin (preferably not based on a centralized service) where one could easily leave comments on any site even if the site itself did not support comments.