I've noticed this in use at a couple of my favorite blogs now, including dk's Chess Improvement and Liquid Egg Product, and finally got around to working with it.
It looks like a nice upgrade from v. 1 that I used previously, but anyway both are available here. Having the annotations in the same window is a step forward. In order to test it out I put in a game that I'd had trouble getting to work with the older version, and found out that the tricky part is that Blogger removes "unnecessary" spaces, which fouls up the cut-and-paste.
Anyway, let's take it for a test drive...
(Later--well that didn't work out so well, diagram too wide for the column and you cannot edit the post after it's published--a blank screen shows in the editing box. Hmmm. Okay, I'll try changing the height and width in the image!)
(Even Later--no I had to change the dimensions of the main column and sidebar--please tell me in the comments if anything looks wrong to funny, or if the new viewer seems good, bad or indifferent to you)