There are two different kinds of blogs that are being referred to here so it's a bit confusing.
The OP is talking about his personal blog on ECF.
Also, a member can link to their blog elsewhere, maybe on Blogspot or Wordpress or whatever, assuming it passes our review. They can't link to it unless it passes. The reason is that some people set up affiliate sites to make money and then call it a blog, but there is no real value to ECF members and it's just a money-making scheme. However if the blog has useful or interesting content, and makes it clear to visitors that there are affiliate ads, it will probably pass as acceptable.
People have to generate an income to pay for their costs, but there needs to be some value for visitors.