Watch the Accompanying with Lead online guitar lesson by Tommy Emmanuel from Fingerstyle Milestones
Getting together and jamming with other players, learning from them, and handing on whatever information you have is a really good thing and a really important part of being a real musician. Say for instance I met up with another player and he asked "Do you know Avalon in C?" and I would say "Yes." Some of the things I might do is play the melody with him. When it's time for him to take a solo, what will I do? Well, I'll use my skills to provide a good backing for him that won't get in the way, that will be supportive and musically right and hopefully inspire him to play his solos. So I've supported him or her with my boom chick bass, spelled the chords out, and played some little chords as well. These things are all important to learn, and they're all good tools to have your musical conversations with other musicians.