Staunch social media enthusiasts have rung the death knell for email.

The presidential campaign shows these doomsayers are full of it.

“Most of the $690 million Obama raised online came from fundraising emails,” reports Bloomberg Businessweek.

You might know these emails, which began with overly familiar—some might say creepy—subject lines, such as, “Hey,” or, “Do this for Michelle.”

Turns out, they brought in millions for the campaign.

Obama’s camp shared email figures with Businessweek, including the amount of fundraising dollars each subject line reaped on one day of the campaign (June 26).

They tested a number of email subject lines—a common practice in the campaign—the most successful being, “I will be outspent.” It raked in $2,540,866.

Some of the other top earners that day:

• “Some scary numbers”— $1,941,379
• “If you believe in what we’re doing” — $911,806
• “Last call: Join Michelle and me” — $894,644
• “Would love to meet you” — $755,425
• “Do this for Michelle” — $714,147
• “Change” — $711,543

As The Atlantic Wire noted, the top three earners on June 26 were “guilt-trippers.”

Over the course of the campaign, guilt-inducing subjects lines weren’t the most successful. That honor went to casual introductions. “Hey,” for example, brought in millions of dollars, according to Businessweek.

The lesson is that a familiar tone beats one that’s more formal.

“The subject lines that worked best were things you might see in your inbox from other people,” Toby Fallsgraff, director of Team Obama’s email staff, told Businessweek.

Is that what you’ve experienced?

RELATED: 7 tips for crafting irresistible subject lines