I wouldn't be surprised if this were true because John Mayer, like Ashton Kutcher, does seem obsessed with Twitter. Well, that's the reason "they" are saying that Jennifer Aniston dumped John Mayer (and not the other way around).
I could just imagine that conversation between Jennifer Aniston and John Mayer:
"John, either you stop Twatting or it's over."
"Hey, I'm still waiting on the world to change and Twatting is helping me do that."
[With tears in her eyes] "John, it's obvious you love Twatting more than me, so it is soooo over."
"You know what, Jennifer? Maybe if you could stop being so insecure and just let go of Brad Pitt, things would be so much better between us. Oh! That would make an awesome Twat."
"I'm gone, John. You are so uncool."
I bet that's exactly how it happened. Poor Jennifer Aniston. John Mayer chose a computer twat over, well, you know...