Craig Newmark founded Craigslist.com in 1995 as an email distribution list of friends, promoting local events in the San Francisco Bay Area, before it became a web-based service in 1996. It was founded in 1999 as a private, for-profit corporation and has subsequently expanded to include an increasing number of locations.

Craigslist creator Craig Newmark felt alone as a relative newcomer to San Francisco after observing people supporting one another in friendly, social, and trusting community ways on the Internet via the WELL, MindVox, and Usenet. He made the decision to do something similar for local events.

Early in 1995, the first emailed San Francisco event listings appeared. The early technology had certain limitations, but by June 1995, new software had been installed to better handle the developing website, and the mailing list "Craigslist" had resumed operations. The majority of the early postings were provided by Newmark himself, and they were notifications of social events of interest to software and Internet engineers living and working in the San Francisco Bay region.

Rapid expansion was soon achieved by word-of-mouth. The number of subscribers and postings increased quickly. There was no moderation, and Newmark was astonished when people began uploading non-event information to the mailing list. People looking for technical opportunities discovered that the list was a useful method to reach people with the talents they needed.