I started using 4.2.2.1 in early 1999. A friend of mine was a sysadmin at Genuity (then the new owners of that block) and they used it a lot internally. I went on to show it to a lot of my fellow sysadmins and I guess a lot of other folks did the same.
Not that anyone cares who wasn't there... BBN was purchased by GTE in 1997. GTE merged with Bell Atlantic to become Verizon. Genuity was spun off, and after it foundered ("Black Rocket") it was purchased by Level 3.
Prior to that, parts of BBN were sold off, and still exist as a subdivision of Raytheon.
Source: I was there for too much of it.
What we told people outside the company about 4.2.2.x: it's there, you can use it for testing or bringing up new systems, please don't use it long-term or heavily. It works by Anycast: let me tell you about that...
