Street style is clothing that is regarded as having emerged from the streets, not from high-fashion boutiques, and not from the artists who create it. Street fashion tends to be most obvious in large metropolitan cities, and is generally thought of as representing youth culture. A lot of street wear brands are especially created for this kind of audience. However, this does not mean that all styles of urban wear are created equal, with some styles definitely better than others.
It is often said that social media has influenced the whole street style industry. This might be true when we consider that most fashion weeks feature celebrity style, as well as that which many young people would like to copy (or at least look similar to). However, it is also sometimes true that social media has done little to directly effect this kind of fashion, as a lot of young people still wear the same kinds of t-shirts, jeans, shorts, and shoes that they have always worn. Some of them may have changed their style to accommodate the way things are being worn, but the core elements remain the same. For instance, it is hard to argue that the vast majority of young people still love the taste and color of tee shirts.
Urban fashion trends tend to be influenced by subcultural beliefs and ideas. As these beliefs change, so do the styles and trends. As an example, there was a time when the entire culture of skateboarding was completely subcultural, and people wearing these types of clothes were widely shunned and discriminated against in mainstream society. Nowadays, however, many people take part in skating competitions and even live in flats that resemble skateboarders. There is no real indication of any subcultural movement existing anymore, except perhaps that the mainstream culture continues to be more accepting of the kind of styles shown on subcultures such as skateboarding.