If you use a trademarked term because you are selling products bearing the trademarked term, then you probably have a legitimately reason to add them to your meta tags. However, I would still recommend that you ask the trademark owner for confirmation.
But, if you use a trademarked term simply to “trick” visitors into thinking they are at the trademarked company's site, you are very likely to get into trouble.
A number of sites have had injunctions placed by judges who decided that the use of the disputed trademarked term was a trademark infringement and represented false representation.
But there was one site that used a trademarked term and won their case, as they proved to the judge that they had a legitimate reason to use the trademarked term. However, that is the exception, rather than the norm.
I suggest that you make sure you have permission to include trademarked keywords in your meta tags. Search the “United States Patent and Trademark Database” to find out if a keyword is trademarked.
Here is a list of other commonly used Meta tags that are generally not recommended for search engine optimization purposes. I have provided the list for your reference only.
<META NAME="author" CONTENT="author name">
<META NAME="date" CONTENT="date">
<META HTTP-EQUIV="content-type" CONTENT="text/html; charset=characterset- name">
<META CONTENT="30 days" name="revisit-after">
<META HTTP-EQUIV="content-script-type" CONTENT="type">
<META HTTP-EQUIV="content-style-type" CONTENT="text/css">
The Robots Meta tag lets you instruct search engine spiders whether they should or shouldn’t index, or archive, the page and crawl the links found on it. Some search engine robots do not recognize the robots Meta tag.
Therefore, I always recommended that you use Robots.txt files where possible.
The content of the robots meta tag contains directives separated by a comma. The "index" command specifies whether a robot should index a page. The "follow" command specifies whether a robot should follow links on a page.
To add a robots meta tag to a page, place the robots tag between the HEAD section of a page.
Here are some sample code and what they do:
Instructs spiders to index the page and follow all links:
<META NAME="robots" CONTENT="index,follow">
These are the default values, so you really do not need to add the tag above.
Instructs spiders not to index the page, but follow all links:
<META NAME="robots" CONTENT="noindex,follow">
Instruct spiders to index the page, but not follow any links:
<META NAME="robots" CONTENT="index,nofollow">
Instruct spiders to neither index the page, nor follow any links:
<META NAME="robots" CONTENT="noindex,nofollow">
Instruct spiders not to archive (cache) a page:
<META NAME="robots" CONTENT="noarchive">
Instruct Google’s spider (Googlebot) not to archive a page:
<META NAME="googlebot" CONTENT="noarchive">