问题
what meta-tags in the header of an (x)html page should be enough for SEO whitout overload it?
回答1:
A few years back, meta tags were important to search engine optimization. However, they've been abused and are generally ignored by almost all search engines (including Google, Yahoo and Live search).
The most important tags for SEO that you can include in your (X)HTML are the <title> and <meta name="description"...> tags.
<title>should generally be what you'd want the search engine to name your page in it's listing.<meta name="description"...>can sometimes give the search engine a basic idea of how to describe your page when indexing it.
However, using these two tags will not necessarily make a difference in increasing your site's visibility on a search engines listings. For more information on that aspect, Google has a nice section on SEO on their site.
回答2:
<meta name="description"> can be used to display a short summary of the site in search engine results, although that's not strictly ‘SEO’.
No others are necessary; in particular <meta name="keywords"> is a no-longer-relevant waste of your time.
回答3:
Description tags though not critical for higher ranking are absolutely critical for true Search Engine Optimization. The goal is not solely to rank highly but to get traffic to your site and conversions. The Description since it is shown on the results is absolutely critical for that purpose. Title and Description are the key elements. Page content is the most critical.
来源：https://stackoverflow.com/questions/666016/what-meta-tags-in-the-header-of-an-xhtml-page-should-be-enough-for-seo-whitout