On September 21 Matt Cutts from Google's Search Quality Team posted a blog article that verified something that most developers have known for awhile now: Google does not use the "keywords" meta tag in its web search ranking.
For the uninitiated, meta tags are HTML elements used to provide structured metadata about a web page. In the code of the web page these elements go in the head tag. In the early days of the Internet and search engine development, meta tags were used to correctly classify a web page. Developers and so called search engine optimization (SEO) experts pushed meta tags to their limit by filling them with information that would propel their sites up higher for search results. Because these elements were designed to be used and seen only by search engines, human visitors to a web site would never see this content, the practice of "keyword stuffing" became popular.
"...disregards keyword metatags completely. They simply don't have any effect in our search ranking at present."
Other meta information is still important today and Google readily admits that they use some of these other meta elements at least when it comes to displaying search results. For instance, if Google finds your meta description to be especially relevant and useful they might use it when displaying search results for your website. And of course any reputable search engine will honor the meta robots tag. This element is used to notify a search engine as to whether or not they can index a web page when they come across it. It can also used to let these engines know whether or not they are permitted to follow the links on that web page. Take a look at this page for a complete list of meta tags that Google understands.
And here's the video that Google released explaining their use, or otherwise, of some meta tags in greater detail.
MSSmartTagsPreventParsing is automatically set to TRUE for every web page. Microsoft's Smart Tags were a proposed feature of Windows XP that would allow Microsoft and its partners to insert their own links into any Web page viewed through its Internet Explorer browser. Setting this meta tag to TRUE prevents Internet Explorer from doing this as it's not a popular idea to allow a third party to control and select what is linked.
Our clients have complete control of the meta description, keywords and robots tags. Any values set for the home page will automatically be associated with every other page of the site. However, it's possible to override these values on a page-by-page basis to give specific control.