Your picture can be viewed only if you give a password to the person with whom you are conversing.
The idea is presumably to safeguard people from searching for their own spouses on the site - though how a husband would explain to his errant wife how he came to stumble across her picture on a website for adulterers, I don't know.
The best part, however, is that if you swipe yes, and the other person swipes no, they'll never know. You can change which images appear, but only to other photos from your Facebook account, by going to your profile, accessible through the menu located in the top left hand corner of the app.
Postings such as: "I want a man who can look after me and knows how to treat a woman. I'm surprised and unsettled by the forward tone of some of the material. Determined to avoid the connotations, I reply: "The Beatles." I never hear from her again.
One woman sends me a message heavily laden with sexual innuendo and I come to regard her as the mistress of the single entendre. Another woman's first contact with me included a plan for a day out together, including visits to art galleries, a stroll round a park and then "a few hours under the duvet". I'm later propositioned by someone who tells me she has an hourglass figure.
After a quick search, I get the measure of the women on the site.
"My preference is for a man who is much younger than me with rugged features," says one. This is a way of paying someone a compliment without typing out the words. And over the course of a week I get almost 100 replies, messages and propositions.
Tinder is the mobile dating app that makes meeting new people as easy as swiping left or right.