First of all I must state that we are not lawyers and nothing in this article can be taken as a definitive statement of fact. It is our opinion based upon following cases closely online. It should be regarded as a collection of information on trademark infringement in meta tags from other sources.
In order to determine if you are infringing another's trademark it is necessary to define a trademark infringement. It could be described thus:
Trademark infringement is use of another's mark that is likely to cause consumer confusion, or to cause mistake, or to deceive as to source, affiliation, sponsorship, origin or approval.
Some of the bigger companies in their fields have been using bullying tactics to stop any mention of their name or trademark in another website's copy or meta data. This is regardless of the context, and whether it is totally benign. An example of this is in the competitive market for memory foam mattresses. Tempur has long been the principle supplier of these products, but since their patent ran out the market has been awash with alternative products. Consequently Tempur has been sending very heavy handed letters out to competitors wherever their name has been mentioned in web copy or meta data. These have been demanding companies to stop "infringing their trademark". This is a blatant attempt to bully legitimate competitors who have not been trying to deceive the customer or pass themselves off as the original Tempur.
The aim of these larger companies is to use their muscle to bully the smaller companies into backing down with the fear of an expensive lawsuit.
Quite frankly we agree with many others in our industry that this is a waste of resources and a lack of understanding of how to use the web to actively market their products correctly. Fair enough, if someone is passing themselves off as something they are not, this is fraud and should be dealt with. But it's sour grapes to complain because a competitor has put the effort in by using effective search engine optimisation and gets results than themselves.
More information : A Review of Trademark Infringement in Meta Tags