A little bit of PSINet history, digged out at the great Google Usenet Archive:

• 15 Jan 1990: Commercial TCP/IP WAN Service
• 01 Feb 1990 : PSI Signs Agreement With RCI
• 14 Feb 1990: Mail & USENET News Service
• 17 Apr 1990: mark Fedor testing Usenet ;-)
• 30 Apr 1990: PSINet 500Kbps WAN Service
• 11 May 1990: PSINet goes Coast-to-Coast
• 05 Mar 1991: PSI Offers New Internetworking Service
• 26 Mar 1991: A Milestone: The Commercial Internet Exchange (CIX)
• 10 Apr 1991: Mark Fedor's squirrel ;-)
• 24 Apr 1991: PSI Announces New Service: LAN Dialup Connection Service
• 24 May 1991: PSI's HOST-DCS is Now Fully Integrated with X.25 PDN Services
• 15 Jun 1991: News about Fedor's squirrel ;-)
• 01 Jul 1991: Electronic White Pages
• 06 Aug 1991: PSI Announces New Service: After Dark Service, or ADS
• 17 Sep 1991: PSI Introduces Global Dialup Service (GDS)
• 05 Oct 1991: PSI Announces PSILink(SM) for Personal Internetworking
• 23 Dec 1991: NSFnet goes commercial
• 09 Jan 1992: PSI Announces Host Dialup Connection Service Plus (HOST-DCS+)
• 13 Feb 1992: PSILink - Personal Internet Access for the PC
• 12 Jun 1992: PSI Enhances PSILink Service, Adds Support for Wireless Data Networks
• 15 Sep 1992: Cascade and PSI Sign $10 Million Contract
• 19 Nov 1992: PSINet Expands Access in Washington and Oregon
• 20 Nov 1992: PSINET EXTENDED THROUGHOUT THE PACIFIC NORTHWEST
• 20 Apr 1993: PSI Creates Three-Way Frame Relay Network
• 17 May 1993: Re: Is PSInet that bad?
• 25 Aug 1993: t.v. stars 'r' us ...
• 27 Aug 1993: PSI/Continental Cablevision Plans to Deliver Internet Over Cable TV
• 16 Sep 1994: PSI and Intercon begin shipping InterRamp software
• 16 Sep 1994: PSI to resell Microphone for InterRamp
• 12 Dec 1994: Thread about PSINet and Spam (C&S)
• 17 Dec 1994: Another thread about the C&S story
• 23 Nov 1995: Dial-A-Book
• 31 Jan 1996: PSI threatens 2600 with legal action