Take flat even light (such as a soft, overcast day), ordinary (or ordinary looking) people and photograph them in a deadpan way, often head on. Preferably with big film (4x5 or 8x10) - oh and if you can throw the words adolescence, pubescent or teenage in there - or a scrawny semi-naked long haired guy - all the better (though non of it even comes close to Sally Mann's or Andrea Modica's or even Lauren Greenfield's take on those first three themes).
I think that looking back it will be very easy to identify this kind of work as from a very specific time period (the early 00's?) a bit like the identification between Duran Duran and 80's music.
It's been done to death and yet every week it seems a new emerging photographer pops up with the same take on the same old stuff. It looked good the first time, in the hands of one of those listed below. But on the whole now 98% of it is - well, pretty boring.
(Note: I'm only including photos in this post by some of those who pioneered this approach, not the followers - this is the good stuff... if you want the endless copycat stuff you'll have to find it yourself)
Rineke Dijkstra perfected this and her work still stands far above most of the rest. Philip-Lorca diCorcia takes stunning portraits which simply defy this (downward) trend.
Along with Dijkstra, Struth was one of the earlier experimenters with this format as was Thomas Ruff. Both did it well, very well indeed.
Loretta Lux took it to a whole new level (and, incidentally, took one of the first truly worthy moves towards the challenge of 1's and 0's, as well as turned the whole trend on it's head) - but stand by for the tidal wave of Bell Jar clutching disciples following in her wake
Martin Schoeller developed a close-up form (used to try replace Avedon for a while at the New Yorker), put his own twist on it and again that worked pretty well. While someone like Alec Soth picks up on an earlier tradition of portraiture and successfully runs with it.
Even so, few of the whole crop of efforts succeed as well as say Sander. I haven't yet seen the colour equivalent (in terms of depth, resonance and impact) of his work. I also doubt that, with a few notable exceptions, most of these will have the staying power of a Cameron or a Sander or an Avedon/American West portrait.
In the hands of the innovators, this approach to portraiture was somewhat refreshing. And (perhaps unfortunately) it works extremely well as a commercial look for selling fashion - or just about anything else - but in general, as a form of portraiture, it seems inherently lacking and self-limiting. I think it's also a very attractive and relatively easy form of work to take up for a whole generation of young things coming out of art school (especially, though not only, because you can use your anorexic/deadbeat/adolescent/gay/lesbian - insert word of choice - peers/siblings as an easy pool of models), but with a few exceptions, it has little staying power. Surely it's about time for something new and better to come and take its place.
As for links to examples - I'm pretty sure you can find them yourselves...
(BTW that's Boris Mikhailov in Soth's superb picture with the carrots)