One who gains a significant following through digital media.
Micro-celebrities have been connected to what has been called the celebrity economy.  They often operate in a specific niche. Examples are beauty bloggers, travel vloggers, or Let's Players. Typically famous within that nice alone, micro-celebrities typically do not appear on mainstream media. As their fame is embedded in social media trends, microcelebrities have been typified by their transience .
Alice Marwick and danah boyd note that a micro-celebrity is “a self-representation technique in which people view themselves as a public persona to be consumed by others, use strategic intimacy to appeal to followers and regard their audience as fans” 
1. Haag, P. (2017). The Rise of the Micro-Celebrity. Big Think. See http://bigthink.com/harpys-review/the-rise-of-the-micro-celebrity.
. Marwick, a. E., & Boyd, D. (2011). I tweet honestly, I tweet passionately: Twitter users, context collapse, and the imagined audience. New Media & Society, 13(1), 114–133.