Is there any consumer marketing data on the willingness of e-mail recipients to open unsolicited e-mails with the "re" prefix in the subject line?

Using a "Re:" prefix, here's how Barack Obama's campaign is responding to Patti Solis Doyle's charges of nastiness:


Marc --

When I decided to run for president, I accepted that my opponents would dig through my record looking for something to attack.

I didn't realize they'd go all the way back to kindergarten.

I'll respond to each of the Clinton campaign's desperate attacks directly and honestly. But when I respond to each attack, I want to be able to say that I am not alone.

I want to be able to say that 10,000 people responded with me in the first 48 hours. And we're almost there.

Respond now with your donation of $25, and show our opponents that this kind of negativity will only make us stronger in our determination to bring about the change America needs:

https://donate.barackobama.com/costofnegativity

It's going to take all of us to change this game once and for all.

Thank you,

Barack

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