I did some research into old 4chan archives and forum posts last week to try to find info about four boards' origins that seem to be largely unknown outside of these vague estimates I pieced together:
>/u/ - Between December 12th, 2003 (pic related) and February 28th, 2004
>/cm/ - Between March 30th and 31st, 2004
>/m/ - Between April 6th and August 9th-12th, 2004
>/j/ - Before October 1st, 2006
I'm grateful to /qa/ and /m/ who helped me narrow down things a lot in making these ranges in the first place, but I haven't found much else since asking them. Could someone please spoonfeed me old screencaps with board lists or browsers visible like pic related? Ideally ones taken between 2003 and 2004 would help the most.