And the mock ads at the bottom.

ETA: Explanation: Sometimes the banner at the bottom will contain an actual (randomized) ad, but many of the comics have their own funny mock ad associated. (When I noticed this, I went through all the ones I had already read again, to not miss out on that content.)

(I thought I'd clarify this, because this comment got downvoted - possibly because the downvoter misunderstood it as sarcasm?)