When i discovered the world of modern knitting last year, i kept bumping into a strange abbreviation - KAL. Turned out it meant "knit-a-long". Folks choose a pettern, colour, theme etc, a timeframe, and all of them knit it, sharing pictures, knowledge and stories during the process.
I am not that much into collective crafting actually, but found those useful (for learning new techniques that might be difficult) and especially for sharing with others - both with giving and receiving feedback.
I was very joyful when i discovered a few days ago that a group of knitters has chosen one of my patterns for a KAL - as it was completely unexpected and i never heard of any of them, it was especially nice. They are kind folks and are doing it on ravelry, so if you are (or plan to) become a member: the pattern is 41g scarflet (also available free on this blog - the first link is for its Ravelry page) and the thread for the KAL is here. It runs thru the end of September but you will not be frowned upon if you happen to join them later, methinks. One of the members is now making her second scarflet already and plans for a third one.