Foolish newbie question

Not foolish at all. Clans are groups of people that generally have a similar interest in what they want to get out of the game or times they are available etc to play. They are worth joining for the fun of playing with people that you like hanging with and for some of the strikes etc that you need multiple people for its a lot better than random matchmaking (in my opinion). If you are interested in joining check out this page for a list of them and then you can follow and see if any look like a good fit. Good luck and welcome to the group! http://www.dadsofdestiny.net/clan-connection-main/clan-connection-list/