Paid review business is now increasingly popular, this is one alternative that promises to get money from the internet. The increasing popularity of this business makes a lot of people are interested to dive, so it starts unequal number of bloggers who are monetizing the blog than the number of advertisers who are interested in the promotion through this pathway.
It also makes not everyone can taste the sweetness of this business, because of competition from other bloggers, or maybe one strategy in building a new power to attract advertisers from the blog under its management. Patience to build this blog into one of the major constraints.