Yes, in the old profile format (the one still in effect), you just post the url of the blog in the description of yourself. However, there will be a change to a new profile (which they've given us the option to switch to now if we like); in it, there's a section in the upper right corner of it for links to social media where people can follow you, and one of them is for "your website". In the new profile, you'd have to put your blog in the "your website" link. That's what I did for my main blog that I wanted linked on my profile. As far as in Hubs themselves, you can only have two links to one site. I don't know about affiliate links.