Joel is funny. not comically funny, but enjoyably funny, such that you can almost always get through a post or interview or whatever without feeling labored.

Joel always brings in metaphors or stories from worlds outside development (only sometimes funny). Many stories still go back to the Army, or his first job at the bread factory, but the recurring stories make you feel like you know him, you know his past, his experience at Microsoft. You know his whole personality through his vast writing, and it's all masked in "clear and prolific and useful" writing.

You feel like he's an expert, because you didn't notice that he's always injecting personality, where, an example from AVC's comments is Mailchimp, who makes their entire brand about a single chimp.

It will be hard for Fog Creek to keep their brand after Joel leaves, but it won't be hard for Mailchimp