I posted on the truce signed in Sangin province with the Alikozai which is the largest in the area. At the time I speculated that it might be due to the beating the Marines had been giving them recently. Well it seems these thoughts might have some merit to them as the Marine Corps Times bloggers have followed up.
You beat someone with the stick (Marine Corps) hard and long enough they come around to get the carrots. This is what happened in Fallujah and the surrounding area in Iraq and seems to be happening in Helmand which has been nothing to a hell hole since 2002 for ISAF forces.