we all know the online foresum a place where you can follow the musings of anybody in 140 characters or less, there are, frankly, disgusting and awful people on twitter. the terror groups are increasingly using it. the question is whether twitter is helping self-radicalized people like the suspected boston bombers. it s a crucial question. and dan rivers has an out front investigation tonight. reporter: away from the physical battlefield, terrorists are creating a virtual one on twitter to spread their ideology. abu barrah follows dozens of extremist on twitter, reinforcing his own hardline politics which have already seen him jailed for urging the murder of u.s. troops in iraq. the reason why people are drawn to the new twitter channels is because there is an opportunity to hear the other