"So, they're looking for Al Qaeda terrirists on Facebook and Tw@tter... Found many?"
They've probably nicked a shit-load of people talking trash and inciting violence. Probably not so many actual bomb plotters.
"I'd say the real reason they do that is because they can and it's easier to sit in an air conditioned office reading some teenager's personal messages for laughs than to do the actual, old-fashioned, put-on-your-dish-dash-and-go-to-the-desert-and-speak-to-some-arabs kind of actual intelligence..."
Because GCHQ do that, don't they?
SIGINT is what GCHQ do. MI6 go and talk to other people overseas and MI5 bug people in Bromley. You might as well complain that the NHS isn't re-airing enough episodes of Bottom in the wake of Rik Mayall's death.
And do you honestly believe that Facebook is analysed by actually reading teenager's posts one at a time?
And talking to people in deserts is a pretty poor way of getting information in comparison to trawling data. And much more expensive. It still goes on, but it doesn't do much to decrease *domestic* terrorism, does it? Or do you think that some bloke in a village in 'Stan knows more about credible UK bomb threats than the people in the UK potentially organising it?