Irony is so Mainstream
Each decade has certain trends that come and go. The '00s will be remembered as the years in which hipsters came about. Defined mostly by what they are not, the hipster is difficult to pin down, but certain hipsterisms have entered the cultural lexicon as something to avoid: being glued to a cellphone, wearing scarves in hot weather (in this case, 30°C or 86°F), and refusing to enjoy any but the most obscure music.
So Vintage You Haven't Heard Of It
Tongue-in-cheek headlines in trendy, overused typographic styles overlay photographs with instagram-style filters applied. This overall look is just on its way out of vogue now, but appeared everywhere from around 2006 to 2014, give or take a couple years. These posters seek to capture the style of the time period while lightly mocking it, a self-aware irony that is very much a part of hipsterdom.