MORE TRAFFIC
Being a blogger is the road many people take. It is not a bad choice, but only postings on multiple forums are not going to help. He should be familiar with the tools which can boost up his traffic on the search engine or will get the people to read his blog more than often. Splitting up the blog posts are going to make the viewer to read each page if the content is good. If the post on one page is too long, then it will bore the reader, and the traffic will go away to some other place.
DISTRIBUTION OF KEYWORDS
Blog posts are not going to get the traffic if they are not optimized on SEO tools. Keyword inserting is also the part of that, By splitting the post, will allow the persons to post different keywords on different pages which will make you post boosting on each engine and also allowing the user to find your content by multiple keywords. It would not have been possible if the blog were long and not much engaging.
Also read this: The Importance of a Content Writer in the Current era
POSTING OF ADS
A single page of one big blog, will not allow you to put many adverts on your page. Splitting it up will give you the leverage that you post new type or ads on every page and get the money from that source too. Splitting the ads on your post, along with good content being around it. It will show the google search engine that your blog is the mix flavor and people should come here to get the content they require. A page filled with a long blog with ads around it will make the google dislike your website and eventually with no traffic.