It's amazing how quickly some concepts can become a new standard. No matter where you go on the web today, It's a fairly safe bet that you will run into a round profile picture. Why is that?
Perhaps we can credit the concept to the trend of flat design. As any trend emerge, eventually its downsides will come into light. There will be space for new notions and something different, yet appropriate enough to stay within the premise of the design pattern. Something that evolves the trend a tiny bit. The flat design template re-introduced the simple and clean approach in graphic design, greatly needed some would say. But inevitably, something would have to be done to the overwhelming feeling of too much simplicity. To many straight lines. Too little contrast and variation.
A round element obviously stands in contrast to a flat and square-cornered design. And I happen to believe contrast is quite important in a design pattern. Photographic content (which profile pictures tend to be, obviously) also stands in contrast to said design pattern, so I guess it makes sense to combine the round shape and photography in what has become a great new standard like element in digital design.
Right about every single blog plattform today features this design (including the one you are currently reading) per default. Let's do a little inventory of some other products using the round profile pictures. You might recognize some of these brands...
I'm really fascinated by how lightning fast a concept like this can become so common so fast. To parallel with a diffrent context, Every Frame a Painting (go subscribe NOW) gave some thoght on how text messages gets displayed in movies and tv. Rather than me reciting, go watch the clip now.
And in a postscript type manner - just to make sure you don't think the above round profile pics are one offs - here's a few more.