My memory is getting hazy, but wasn't Gmail originally just (something like) the simple HTML version, and it supported tags and classification from the beginnin

My memory is getting hazy, but wasn't Gmail originally just (something like) the simple HTML version, and it supported tags and classification from the beginning? Like I'm pretty sure I had filters to tag and skip inbox for newegg emails circa 2005 so I could have a separate "inbox" for them. Likewise for some mailing lists I was part of.