Why is this site called e621? Where does the name come from?

Is it dedicated to the e-number of msg?

Indeed e621 is named after the chemical MSG which is a flavour enhancer - because e621.net enhances the flavour of the Internet XD

The site started as an experiment between a small group of friends with little expectation of ever becoming as popular as it is today. The domain name e621.net was chosen arbitrarily from one of many parked domain names the site creator owned at the time.

Caroway said:
The site started as an experiment between a small group of friends with little expectation of ever becoming as popular as it is today. The domain name e621.net was chosen arbitrarily from one of many parked domain names the site creator owned at the time.

source?

from what I've remembered reading the name was chosen because e621 = MSG & MSG = "meaty" ∴ e621 = meaty

edit: Yeah, here's Ratte saying pretty much exactly that: forum #239962