"META" tags are all but useless, and only useful at all if they are carefully created by human evaluation and judgment. Any attempt to create automatic ones is not likely to produce any meaningful result.
That's not true ! Lot of search engines rely on meta tags. The only search engine we get lot of traffic from is Google (which ignores META tags). The rest are almost ignoring us and this is one of reasons.
That's one reason why Google is the only search engine that matters; they discovered long ago that META tags provided no useful information, so they evaluated pages on their own.
Information is only useful when it is honest and accurate. Because search-engine rankings are economically valuable, the natural incentive is to manipulate the self-descriptive information in META tags to achieve the result, rather than making them honest and accurate. Because of that, search engines that use META tags rank highly those who are most adept at manipulation, not those of most real value.
I would not oppose some means of allowing authors to add META tags that were honest and accurate and based on human judgment. But if we created META tags by some automated process just to get higher rankings on search engines that still use them, then we would be guilty of manipulation just as other advertisers are.