I think it is. Just like with all forms of social media, there are good and bad parts. Depends on who you follow, circuit, etc..but i stick with the people I respect, and leave the rest alone.
Im not touting him because he posts here, but Serling is a great follow. Not just for on the track, but he's a pretty sharp dude. Richie Migliore as well..hell all the NYRA folks bring a lot to the twitter machine.