SPAM comments and paying attention
One of the really cool things about Disqus comments is that it will not only import all of the existing comments from Blogger's native comment system but it will also keep comments synced with Blogger. If someone hosting a blog on BlogSpot.com (with or without a custom domain) ever decides to go back to Blogger's native comment system, all of the comments are still there plus all of the new comments added via Disqus are there too.
That is, unless you're an idiot.
The only problem with installing Disqus is that I have been inundated with spam comments on Blogger's native comment system as the restrictions on anonymous comments have to be turned off to make Disqus work properly. The spam comments never show up on the site, but they are in the spam folder. So every now and then I go in and clear out all of the spam comments. When I did that on Tuesday, I did not check to confirm I was in the spam folder instead of the "published comments" folder and I deleted all of the comments in Blogger's native comment system.
The good news is all of the comments are still there. The bad news is they are only stored on Disqus, so if I go back to Blogger's native comment system I lose all my comments. Also, if Disqus urps like it did last summer and loses my comments (although I am pretty sure that was my fault) there's no backup in Blogger's native comment system for the old comments.