by MCarusi on 6/3/14, 11:58 PM with 1 comments
by anigbrowl on 6/4/14, 12:20 AM
Otherwise, almost anything goes - you can trademark colors, logos, fragrances, and what-all else. The basic requirements are that a mark be distinctive - ie easily identifiable - and that it be used in commerce (at least in the US, because trademark registration authority derives from the Commerce Clause in the Constitution).
This trademark seems to have been properly filed, brought to public notice, and issued. It has no effect on the use of Pi in math books, computer code, discussions like this one, or most other categories, but it does apply to the use of the symbol on athletic/casual clothing. Sucks, but it's legit. Y Combinator could equally trademark the 'Y' logo that appears in the top left corner of HN for use in the context of business development, and someone would write a story along the lines of 'Investor Paul Graham trademarks the letter Y.'