Like a lot of things on the internet, it just seems like we like to find a sense of community by labelling ourselves or building an identity. And I'm sure there is an impostor syndrome support group out there somewhere.

In a deeper sense, I feel like there's also a growing desire to express vulnerability, and so hearing people talk more openly about this stuff doesn't mean it's a trend or that it's invalid in some form, it's instead bucking the trend of dealing in silence.

The truth would sit somewhere between those angles.

http://www.paulgraham.com/identity.html