There's some confusion over the definition of "affiliate link", so let me expand on that.
An affiliate or referral link to a reputable site like Amazon.com, your favorite camera store, craft store or similar, where you make a commission or get a discount for referring sales - these are generally fine in the context referred to above (i.e. real blog, original content, discreet and appropriate link). But no banner ads or spamming please, and no blogs that consist of nothing but "buy now" links.
"Affiliate links" as in clickbank, usercash, megabuxcashmillionstrafficpro, affiliate/network marketing programs (including those masquerading as fitness/forex/weight loss/cosmetics/etc), paid/sponsored posts, text link ads, lead generation affiliate programs, paid links to porn, drugs, casinos, payday loans, and whatever other potemkin "legitimate product" the Get Rich Quick crowd are selling this week = no no no.
This is stated on our Types Of Blogs page, albeit briefly:
Again, "real blog" is the key. If you have a real blog with real content and link to something we don't allow, we'll warn you with an alert in your dashboard and ask you to remove it. That's ok, we're not going to punish you for it or yell at you or take your blog away. We like real blogs and do our best to keep them around even when they inadvertently break the rules.
And to clarify "real blog", we mean blogs written by and for humans. Copy-pasting a bunch of content from ezinearticles or amazon reviews does not a real blog make.
I'll defer to Mark on any of the specifics if he'd like to chime in.