A new smartphone app called SceneTap made a big splash with its recent launch, but not all of the reviews were entirely favorable. The app employs facial-detection software and cameras placed strategically in bars and nightclubs to tell users the age and gender makeup of an establishment they're thinking of visiting. The problem is that the patrons being scanned by cameras don't necessarily know that they're being monitored. Some privacy advocates call it "creepy." Is it an invasion of privacy for your neighborhood watering hole to install cameras and scan your face? Here, a brief guide to the controversy:

How does the app work?

The people behind SceneTap have installed cameras in bars in San Francisco; Austin, Texas; Athens, Ga.; Bloomington, Ind.; Chicago; Gainesville, Fla.; and Madison, Wis. The cameras use facial-detection software, which unlike facial-recognition software, only picks up on basic data about people and can't specifically identify faces. SceneTap uses this information to come up with a rundown of ages and sexes, so the app can give users real-time updates on which nightspots are full of women, or men, and how old or young the crowd is.

What's the point?

SceneTap CEO Cole Harper says the app helps people find places that offer the type of crowd they're looking for. That, fans of the app say, would help people avoid the hassle of going out of their way to get to a bar, only to be disappointed by the human prospects. "If I was a single dude living in the city, I would use it," says Sean Silva of San Francisco, where the app launched on Friday in two dozen bars.

Is that really so bad?

According to privacy advocates, yes, it is. Let's be honest, says Violet Blue at ZDNet, this "bro-app" is designed to help "brotards" get liquored up and go straight to the bars "with the most chicks in them," which is "sure to make women feel a little more like hunted prey" than they do already. News of the launch in San Francisco provoked so many complaints that several bars that had planned to participate backed out. Critics compare SceneTap to the controversial "stalker app" Girls Around Me, which uses information from Facebook and Foursquare to tell users what spots around town are filled with young women.

What will SceneTap users know about you?

Harper promises that the service won't collect any personal information. "It's not recorded, it's not streamed, it's not individualized," Harper says. According to SceneTap, "You actually give up more information when you hand a bouncer your ID at the door." Sure, for now, says Jennifer Van Grove at Venturebeat, but who's to say SceneTap — which a colleague recently called a "sewer of an app" — "won't start collecting other traits such as height, weight, ethnicity, or wealth" down the road?

Sources: Ars Technica, Consumerist, Eater, Venturebeat, ZDNet