OP here. I'm using readability's old code (arc90) to extract text, and you can use squirt on any page you like--just embed a link with the same JS as the bookmarklet. If you want a real API, add a github issue (http://www.github.com/cameron/squirt) to remind me--it's on my project bucket list :)
I'm not sure what "Spritz technology" is. RSVP has been around for a long time—it may be that they genuinely added to it with the centering and the red letter and the nice pauses, or it may be that they're trying to patent the equivalent of a one-click purchase.