stickiness

Some trends stick and some trends don't. This ridiculous Indian jacket that I'm wearing here, well, it's the kind of trend that you'd only see on fashion blogs, and fashion blogs, and fashion people, basically look like super freak alien versions of people. 

My point is, yes, I do have a point, that the trends an avid fashion blog reader can spot don't always make it to the mainstream, but when they do, you can bet that they were on the fashion blogs months before. 

Malcom Gladwell, in one of his many sociological/cultural critique books for dummies, calls this the stickiness factor. 

Here are some of the reasons why some things are sticky and some... well, they're like this jacket. 
the narrative form- people respond to stories 
influencers- if cool people wear it, other, less cool people will imitate them
the early adaptors and the innovators- pretty much the same as above, people who do things before the mainstream