Once again, I want to stress that I am NOT and attorney, and I am NOT giving legal advice. Take this information and do as YOU see fit. (this legal disclaimer is a pain in the butt, but I don't want trouble by trying to help you).
I found several cases on line regarding Trademarks and Meta Tags. Just go and Google those two terms, you will be able to find information.
DO NOT use trademarks (for example, company names and brand names) in a link, or in keywords. This will VERY likely be construed as a TM violation. If you use the TM in a non link description, you might be ok. It is the META TAG that is the problem
I have also read that owners of TM's are highly encouraged to seek out use of their TM's in meta tags (links and keywords typically...) and pursue violations...if they don't and let too many slip by, the courts will consider that they have abandoned their mark.
If you sell your wares on a site that has you enter keywords, or if you use key words in your blog, be aware of this.
So....off I go to make sure that I have not used a certain Austrian Crystal mfg and cylinder bead name in my keyword descriptions on the hand made site where I sell my goods....