单项选择题

Oh no, not Anthony Weiner again.
The older generation never gets it. Anthony Weiner, a candidate for mayor of New York, admitted this week to having sent more snaps of himself to a digital acquaintance. As any youngster could have told him, the way to find love is to send photos of your face.
Consider Will, a 24-year-old future film director in California. He meets potential dates via a smartphone app called Tinder. It finds potential matches who are nearby—your phone always knows where you are—and shows him photos from their Facebook profiles. Will can like or reject each photo. If a woman he likes also likes him, both are alerted and can start chatting.
Tinder is quick (you can look through dozens of photos in minutes) and spares your blushes (you never know if someone rejects you). Will has already had three romantic encounters and hundreds of matches, he says. Justin Mateen, a co-founder of Tinder, says it has made 100m matches since its launch in September, and led to 50 marriage proposals. He adds: "The app has only really been going for nine months. There could be a baby popping out soon."
Americans are dating longer, which creates opportunities for matchmakers. Some are quite direct.
Bang with Friends (BWF), another app, allows users to specify which of their Facebook friends they would like to spend the night with. If both parties feel the same way, BWF notifies them. If not, no one is any wiser. BWF was booted from Apple’s app store, but that hasn’t stopped it from creating 200,000 pairings since its January launch. BWF’s boss admits he came up with the concept while "a bit drunk."
Such apps make it easier to find potential partners, but don’t seem to have turned America into a nation of bed-hoppers. Young women claim to have had an average of 3.6 male intimate friends while young men 6.1 female ones. These figures may be inaccurate—men may exaggerate; women may undercount—but they have not changed much in years.
Parents worry that staring at screens all day has made youngsters socially awkward face-to-face. A survey by two dating sites found that 36%-38% of Americans aged 21-34 ask for dates by text message. But when they meet, they must still make their moves in person. Witty joking and a well-placed facial expression still have their uses. Potential matches found by Tinder are probably ______.