Twitter is a near perfect example of intermittent variable reward (the key addictive element of slot machines)

Twitter can trick the brain into thinking it's having meaningful social interactions by promoting "a strong feeling of connectedness" while another part of the brain is telling you something is missing.

Twitter is yet another dramatic contribution to the always on multi-tasking lifestyle.

I agree with her 100%. Twitter and technologies like it (telnet talkers and MUDs in the 90's, IRC and so on) are dangerously addictive and having one of them hit mainstream scares me.