I may have been watching too much Homeland, but isn't wiretapping one of the main ways the intelligence community picks up on the "chatter" about large-scale te

I may have been watching too much Homeland, but isn't wiretapping one of the main ways the intelligence community picks up on the "chatter" about large-scale terrorist attacks being planned? Didn't we find Bin Laden's Courier (and ultimately Bin Laden) partially through monitoring his cell phone? Apologies if these are naive assumptions - would love clarification.