It's my impression that there are two basic kinds of jams (and by extension, two kinds of jam buddies).

The first usually involves a big group of people. Songs or tunes are started by specific individuals, either by taking turns or by whoever is extroverted enough to start them. That person chooses the key and sets the pace and chooses when to allow for solos, while everyone else follows along or sits out. When the song is finished, it's finished.

The second usually involves a small group of people, and there's a lot more discussion (I mean relevant discussion, not gossip) about what songs to play, what keys to play them in, what tempo, who should play what instrument, and who should have a solo when. When the song is finished, they might do it again with something done differently, and do it again next jam session too. Sort of like a band working up songs for performance, but without the bother of actually being a band or performing.

I'm not sure which way is more educational - I guess it's probably the most educational to do some of both - but I certainly enjoy the second way more.

Marion