Twitter has seen a huge increase in political activity this election year compared to the last, making it a new and growing frontier for threats that fall under the Secret Service's jurisdiction. In February, a Florida man was charged with using social media, including Facebook and Twitter, to make threats to assassinate President Obama, as was an Alabama man who used Twitter to threaten the president last month during the Democratic National Convention. The Secret Service also evaluated a threat sent through Twitter by a 16-year-old girl in Ohio in September.

Twitter users have posted threatening messages against Mitt Romney as well, some suggesting that Romney’s hypothetical election in November could trigger an assassination attempt. Such threatening tweets recently prompted several conservative sites to raise concerns that the threats against the GOP challenger were not being taken as seriously as those against the president. The agency countered that it was “aware” of the threats and would “conduct appropriate follow-up if necessary," according to The Weekly Standard.

In fact, using threatening language in political tweets has become so commonplace that it rarely makes headlines when the Secret Service investigates. The agency evaluates such tweets to see if they qualify as a serious threat.

“We cast a wide net for information, and that includes law enforcement agencies, federal agencies and the general public,” Secret Service spokesman Ed Donovan told the L.A. Times. “We’re not an intelligence agency — we’re consumers of information.”

Donovan emphasized to the Times that the Secret Service is asking people to call in tips, rather than report threatening tweets through Twitter to the @SecretService handle.

With more than 300 million tweets sent every day — and heightened interest in the election less than two weeks away prompting stronger rhetoric online — the agency does not consider social media reporting the best method to flag serious threats.

The Secret Service protects numerous current and former political figures. Obama in 2008 became the earliest presidential candidate to receive the agency’s protection, 18 months before the election. Romney got his own detail this year in late January.