In mentoring some new agents, I always tell them that Active Rain can be a great source of business, and they should consider blogging on the site.
The most frequent objection I get is the perennial "I don't know what to write".
I had that conversation with a new agent just this morning, and I told her not to worry about what to write. In fact, why don't you write about "I don't know what to write"?
Just a couple of paragraphs... 'cause the most important thing is to just 'get started'.
I've given her the goal of writing at least one post this week. And once that's done, at least a post each week. Once you break that initial barrier of your first post, the rest comes easy.
You don't have to be a great writer... you don't have to be eloquent... (I'm certainly not)... just write the way you speak.
C'mon, all you lurkers... get started. I'll be your cheerleader!