The game is already 11 years old in concept and design. I believe Stefan and MasterMike started work in February 2000. It is not totally clear when the alpha stage began, but there's some evidence it was April 2000, with the betas beginning in the summer (in the Northern hemisphere) of 2000. Strictly speaking Alphas and Betas are pre-IC*, as they are test phases and the game (round 1) began in March 2001. So actually IC as a non test-phase game has just celebrated its 10th birthday.

* The old-timers are likely to say that this was actually the best time in IC's history. Though (big server crashes aside), IC reached its peak in rounds 3-5 (from mid-July 2001 until about May 2002). IC remained strong for probably another 2 years and in 2004 the community suffered some serious losses - real deaths - and the decline of playing numbers started to become noticeable.