Tagging is used online mainly as a way of categorizing and organising content. Most social media platforms include the option to attach tags to posts however it is more prominent within say Instagram and Tumblr as opposed to Facebook.
SPEEDHUNTERS
Speedhunters is a massive and sucessful blog documenting car builds and events around the world and boasting some of the best photographers in the area. This blog could be an example of the use of tags and features a page where you can choose to voew posts focusing on specific types of cars or disciplines of motorsport.
Michael's blog 9000 