Four years ago, over dinner, my friend showed me a new app on her phone. It served up an endless parade of faces - single men, in our area. I was scandalised.

That that anecdote has already taken on a timeworn quality, like people's first memories of colour television, is testament to just how mainstream location-based dating apps have become since Tinder pioneered the form in 2012.

Now there is Happn, which prioritises people you often cross paths with. Bumble, where the woman must make first contact and has only 24 hours to do so.

Unless you have been in a monogamous relationship for the last half decade, you have probably used at least one of them.

Among younger people, in particular, dating apps have become a low-maintenance, light-hearted way of signalling that you are open to meeting new people and whatever fun and flirty opportunity may come your way.

In reality, that is scores of messages saying "hey"; conversations that fizzle out after a couple of days; or one or two meetings concluded by unspoken mutual agreement.

The banality of dating apps is often lost in the discussion, being less titillating than handwringing over the risk they might pose to our safety and psyches.

Mostly, criticism distracts from the real issues: What do you do when a co-worker comes up?

Or someone you know to be in a long-term relationship?

As an irregular user of Tinder, this raises for me the politics of swiping on people I know "in real life".

Should you give your workmate an affirmative right swipe just to be friendly?

It is arguably a snub to ignore someone you know on Tinder, just as it would be if you were to blank them at a bar.

But I suggest weathering the consequences - the risk of your polite hello being misinterpreted is just too high.

One of the problems with dating apps is that the meaning of a match can be ambiguous. Tinder, in particular, is at pains to stress its potential for forging "connections" of all kinds - some users really are looking to make friends.

Until recently, my bio stated that I was "not looking for serious relationships", which to me spoke of casual, irregular dinner dates with no expectations as to where they might go.

Then my worldly friend explained I was, in fact, explicitly asking for one-night stands - not at all what I had imagined of my appeal for someone to go to the cinema with whenever there is something good on.

Panicked, I overcompensated by detailing my circumstances and expectations with some specificity.

My bio is now longer than any I have seen on Tinder.

A teenage friend recently looked at it askance, then said matter-of-factly: "I guess it's different on adult Tinder."

Another aberration of "adult Tinder" is the quandary posed when someone you know to be happily coupled comes across your screen - more often than you would think, with a wedding photo on his or her profile.

The guilelessness of this supports a common explanation that is just about plausible: that people in relationships give in to their curiosity and download Tinder to see what the fuss is about, then delete it from their phone - not realising that they have to delete their account to stop their profile from being served to singles in their area.

Many Tinder users also do not know it is possible to see a list of their own Facebook friends who are also on the app, through the irregularly used "Tinder Social" function.

My colleague just tried this and found three people he understood to be married and 10 in long-term relationships.

Again, interpretation trumps intention. Many times, I have been messaged a tentative inquiry of a mutual friend: "Did so-and-so break up or ... ?"

In general, I am not in favour of addressing unexpected dating app appearances unless you are certain their presence there is unintentional and they would be grateful to you for bringing it up.

Misunderstandings are likely: What if they have decided to open up their relationship? Or they have just separated and not gone public about it yet? Any offline acknowledgement of dating app interactions is usually awkward.

Dating apps are best used to meet people you do not already know. Still, it will always be a somewhat contrived connection until you have spent some time together in person.

For this reason, I am in favour of resisting the temptation to do a deep-dive on your date on Google or grill your mutual friends for intelligence before you meet for the first time.

For all their popularity, dating apps are still a fundamentally unnatural means of meeting people.

Do what you can to leave yourself open to surprise, to serendipity.

More important is the risk of accidentally exposing yourself by mentioning the person's recent holiday to the Philippines, or his or her overly communicative ex.

Save the online investigation for before the second date, when you can say "You told me last time" - if the person raises an eyebrow.

GUARDIAN