I bought a blog a few years ago. It had a cool name and logo, some good pre-written content, a small but loyal exiting subscriber base, and some decent monetization of that content from ad sales and affiliate marketing. It was a mistaken for a few reasons: (1) I simply was not passionate about the content; (2) I didn't have a solid strategy for obtaining new content. I started writing some of my own, grew bored, then solicited volunteers and spent an inordinate amount of time editing their work; and (3) it wasn't tied to a product or service, which I think you really have to do unless you're a brand name like The HuffingtonPost or something. Between tinkering with Google Ad Sense, a dozen affiliate marketing efforts, and editing, I quickly lost interest. Ironically, I've written guest blog posts and articles on how to develop successful blogs and I wound up making most of the mistakes I've written about.
Blogging pays when you can pinch hit for people that can't carry the load anymore. Maybe at one point in the past they envisioned writing every day but now they can't. Offering your services to someone who cares about good content allows them to look good in front of their friends. Nobody ever has to know they didn't write it.
One of my favorite clients used to post really good writing. It was win win, because I used those links to get all kinds of work. But his site got scrubbed by all kinds of bots. which made him look good on his page views.