NATO officials categorize the Taliban into two types of fighters. Tier one, as they are called, are hardened, ideologically driven men who have come back to fight from their rear base in Pakistan. Tier two fighters are local men who may join the war for a variety of reasons — economic, tribal or religious.-- from Carlotta Gall's article British Make Initial Gains Against Taliban, which gives the impression that the British approach in Helmand is working.
“The biggest change from last year to this year is there has been no tier two mobilization,” [Lt. Col. Stuart Carver, who commands the Battle Group North, ] said. “They have tried,” he said of the Taliban.
See too this account from Sangin by Mark Townsend.
And see the view from Rory Stewart (extracted and linked at Kabul no bull).
[P.S. 9 August: British Criticize Air [U.S.] Attacks in Afghan Region]