According to the law, Microsoft MUST sue in order to avoid what is known as trademark abandonment.
'Marks also may be abandoned unintentionally, through improper use. A mark may be abandoned "unintentionally," when the trademark owner fails to use it properly, or fails to monitor its use by others.'
So according to this definition, if MS feels that their trademark is being misused, they must sue in order to make sure it doesn't become "generic."
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According to the law, Microsoft MUST sue in order to avoid what is known as trademark abandonment.
'Marks also may be abandoned unintentionally, through improper use. A mark may be abandoned "unintentionally," when the trademark owner fails to use it properly, or fails to monitor its use by others.'
So according to this definition, if MS feels that their trademark is being misused, they must sue in order to make sure it doesn't become "generic."
More info on trademarks:
http://www.ggmark.com/protect.html