Since the beginning of recorded time we can see that event blogs are money making machines. If you know, how to do On Page SEO (Search Engine Optimization) or little bit Off Page SEO, you can easily rank on search engines.
Online blogging is a way to reach more people with a perticular topic in currunt era, but the event blogging is totally based on specific event and to target specific users for that time peried.
Bloggers are targeting users with event related content and make handsome revenue from that event blogs and this kind of bloggers called Event bloggers.
Bloggers buy a domain related to the perticular event and work on it untill it rank on first page of the search engine which they are trying to target.