A new PSA by the AIDS Council reminds viewers that they might not be the first to have “checked in” to their partners’ sex lives.

The goal of the campaign — to reduce the number of people having un-safe sex — may not be new, but a surprise social media element definitely is.

The series of ads, created by the McCann Worldgroup Helsinki ad agency, depict heterosexual couples gazing hungrily into each other’s eyes, touching each other’s chests and stripping down.

Right when one member of the pair is about to remove a final garment of clothing, a notification from FourSquare, the location-based social network, pops up saying either “Cathy Mills and 34 others were here” or “Ryan Smith and 19 others were here.” (Yup, the ad agency chose to make the dude have more partners.)

The basic message is, you might not know who else the person you’re having sex with has been with — or what the health consequences of those encounters have been. And the social media lingo clearly targets the ads to young adults. This is especially important, given that nearly half of all sexually active teens and young adults will contract a sexually transmitted infection (STI) by age 25.

LOOK: The second AIDS Council PSA

PLACES for men (english) from McCann Worldgroup Helsinki on Vimeo.

The FourSquare-dotted ad campaign is certainly a fresh approach to educating young adults about safe sex. However, Rebecca Cullers of AdWeek pointed out that you don’t need to sleep with someone who’s had 34 other women or men in their bed to contract an STI:

The main problem I see is that the ads play off fear and contribute to the stigma of sexual promiscuity. We should take care to remember that while your number of partners may increase your chances of getting an STD, it only takes one. Or none, if you’re born positive. So really, there’s no excuse for not wearing a rain jacket.

On the other hand, the AIDS Council campaign has found a creative way to get across an important public health message that other campaigns often haven’t communicated in interesting or effective ways in the past.

Given that high STI rate among teens, it’s a message many apparently still need to hear. Unlike Hannah Horvath of “Girls,” most young adults are not tweeting about their STIs, but that’s where the new campaign is brilliant.

In an era when we text and tweet and post status updates about sometimes too many aspects of our lives, the PSA reminds viewers that STI’s are one thing people usually don’t broadcast about themselves — via any medium. Your Facebook feed isn’t going to tell you whether the person you’re sleeping with has HIV, or if the person she or he slept with last did, and no other service or app will either.

Condom, anyone?

[H/T Jezebel]