I've always looked at pictures from a certain era and wondered, how do you know they're from that era? I think websites have the same characteristics.
Continuous scrolling (seen on Facebook, Twitter)
Sharing via various social networks at the bottom of each article
Pictures: products are photographed with a flat background. There is no distinction between the surface on which the product rests and the background, usually black or white (see: Apple products, Kickstarter). Products are made to look perfect, like they could be computer-generated. Actually, this is also present in video, such as interviewing people in front of a white background.
Row of dots at the bottom with 1 filled/bigger dot indicating more screens to the left and right (iOS home screens)