It's in the wikipedia article:

> Following the case it was suggested by Struan Robertson – editor of Out-Law.com – that Microsoft had little choice but to pursue the issue once it had come to light or they would have risked weakening their trademark.[19] This view was also espoused by ZDNet, who noted that had Microsoft knowingly ignored Rowe's site, the company would have risked losing the right to fight future trademark infringements.[20] Robertson opined that – had legal proceedings ensued – Rowe would have made a strong argument for keeping his domain, as he was using his real name and was not claiming to be affiliated with Microsoft.[19]