Jason Pack sorts them into different groups:
[T]he Islamists, like the army defectors, don't comprise the bulk of rebel fighters. The most prevalent form of unit organization is ad hoc: a few brothers or friends sharing gas money, a few rifles, a rebel flag, and a pickup truck. Occasionally, whole villages or subsections of tribes have joined the rebels as a semicoherent unit. Yet even then, village headmen or tribal sheikhs do not appear to be leading or orchestrating the fighting. In fact, military leadership at the front, inasmuch as it exists, is entirely spontaneous. In late March, for example, the top military brass in Benghazi strongly advised the fighters not to push past Ajdabiya when it was retaken due to coalition airstrikes. The fighters did not obey orders and were quickly routed by Qaddafi's counterattacks.
(Photo: Speakers standing behind a large pre-Gadhafi era Libyan flag now used by the opposition, address a rally held after Friday prayers on the corniche in Benghazi, Libya Friday, April 1, 2011. By Ben Curtis/AP)
The Dish 