I have been using Haloscan, which morphed into Echo and JS-Kit, for my blog's commenting system almost as long as this blog has existed. In 2005, Haloscan offered a better user interface than Blogger's comments, both for commenters (who did not need to register for an account anywhere to comment) and for blog owners (who could easily moderate comments to filter out spam). That advantage eroded over the years, but the system remained good enough to leave in place. As of today, October 1, that system has been discontinued. I will try to switch to a replacement — most likely Blogger's (much improved) native comments or Disqus — as soon as possible. In the meantime, if you would like to comment on a post or say hello, you can contact me via Twitter (@dendroica) or email me at empidonax AT gmail DOT com.