That's very good, glad to read that!
They speak for themselves pretty nicely here: Overview | CloudFlare | The web performance & security company, but in short (and as as as free service for AlterVista is concerned, they do more for money), they bring a caching layer combined with content distribution network in front of the web site, so theoretically you get faster downloads from a CDN server near you and not from the single AlterVista-hosted machine and indirectly that fixes such routing glitches as we see with Comcast (because you no longer connect to AlterVista server but a CloudFlare one).