I don't quite understand that job. Are they fake reviews, custom ordered reviews, and other such dubious things? Like some manufacturer/store introduces a new product and they want (positive) customer reviews immediately to make people think it's a decent buy, so they pay 100 yen to someone to write a review, even if that someone didn't have a clue about the whole thing and had never seen the product. Or was it actually more honest work, writing articles for an ad driven site as a freelancer, basically? The site would need updates and articles to keep people visiting, but it's not so lucrative they could actually hire people to do it full-time.
Or what was it all about?