I've not been happy with the commenting and community functions here at squarespace. While I guess they would work well for a small company or for a site that wanted to build a managed community, I don't really want people to have to manage an identity just for my blog. If a site doesn't allow facebook connect or openid login of some sort, I'm very unlikely to want want to participate. So, I've been very uncomfortable with forcing that on people here.
On top of that, I had hoped that by moving to a solution like squarespace, that I'd find it easier to integrate with my content across the net, particularly facebook and twitter. Although the the tools squarespace provides are quite nice, I have been a little disappointed at the slow pace of development of integration features.
The search came down to two primary candidates: disqus and echo. Both feature commenting systems that can be plugged into an existing site. They both have a wide variety of identity/login options, and they both look to have at least some ability to integrate content with social networks. My impression was that echo had a little bit more of what I wanted, but there doesn't seem to be a true free/cheap level. The product looks very focussed towards small/medium company sites and even their cheapest plan prices me out of the market. I have absolutely no problem paying for a service, but what they offered was just too pricey for my needs.
So, I've added disqus here on the blog. One side effect is that old comments are gone. I'm hoping there will be an easy way to import them into disqus, but for now I'm just going to settle for the blank slate. I hope that if I go with this long term that there will be an easy solution for bringing those existing comments in. And, of course, I'm assuming I'll have an easy way to get comments out of disqus later if need be. That'll all be part of due diligence. In the meantime, I'm considering all comments as transient.