Lovely write-up of Passle over on Equinet. You can read their insights here.
Passle is the only tool on our list that has to be paid for – but it delivers the most value of the four. It essentially allows you to microblog; to produce excellent, high-quality content for your website in a much shorter space of time. Instead of creating your own blog post from scratch, you can build a post around another writer's work, commenting on and perhaps even developing their ideas.