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咖啡以外：Meta KeywordsTag101: How To “Legally” Hide Words Meta Keywords Tag 101: How To “Legally” Hide Words On Your Pages For Search Engines Sep 5, 2007 at 7:42pm ET by Danny Sullivan
The meta keywords tag is one of several of meta tags that you can insert into your web pages to provide search engines with information about your pages that isn’t visible on the page itself. For example, my Meta Robots Tag 101: Blocking Spiders, Cached Pages & More article covers how you can use a different meta tag — the meta robots tag — to block pages from being indexed. Users don’t see this information (unless they look at your source code), but search engines do.
Meta tags go within the header area of your web pages. A typical head might look like this: <head> <title>Welcome To Shoe Central!</title> <meta name=”description” content=”All the best prices on shoes!” /> <meta name=”robots” content=”noodp” /> <meta name=”keywords” content=”shoe, shoes, shoee, shos, footwear” /> </head> The header is the section that begins <head> and ends </head>. Between those elements, in our example, you have these tags: Title: The text here becomes the title that is shown in search engine listings, in most cases. I’ve long written about search engines and meta tags, but I have never been able to pin down exactly who created the meta keywords tag. There’s a December 1995 internet draft memo that’s the earliest and most authoritative mention of the tag I know of. It says: <META HTTP-EQUIV= “Keywords” CONTENT= “Italy Product, Italy Tourism”> The spaces between a comma and a word or vice versa are ignored…. These ‘keywords’ were specifically conceived for exhaustively and completely catalogue the HTML document. This allows the software agents to index at best your own document. To do a preliminary indexing, it’s important to use at least the http-equiv meta-tag “keywords”. Sounds good, right? Like this is designed for the search engines to use? The issue is that HTML specs like these (especially drafts) are not necessarily used by the search engines. They can use them, ignore them or build upon them as they see fit. As it turns out, several of the major search engines got together in May 1996 to talk about meta data. That meeting gave birth to a common standard for the meta robots and the meta description tags. As for the meta keywords tag, it was discussed, but no specification emerged. Despite no specification, both Infoseek (later Go.com, these days no longer crawling the web) and AltaVista (now owned and powered by Yahoo) offered support for the meta keywords tag in 1996. If you looked at their help files at the time, they encouraged site owners to use the tag. Inktomi (now owned by Yahoo) also provided support when it began operations later in 1996, and Lycos (no longer crawling the web) added support in 1997. That year — 1997 — was the last year that the meta keywords tag enjoyed support among the majority of major crawlers out there (4 out of 7 – Excite, WebCrawler and Northern Light, also crawling the web that year, did not support it). Support Dies Off When new search engines emerged in 1998, such as Google and FAST, they didn’t support the tag. The reason was simple. By that time, search engines had learned that some webmasters would “stuff” the same word over and over into the meta keywords tag, as a way of trying to rank better. At the time, search engines didn’t rely so heavily on link analysis, so page stuffing like this was more effective. Alternatively, some site owners would insert words that they weren’t relevant for. In July 2002, AltaVista dropped its support of the tag. That left Inktomi as the only major crawler still supporting it, causing me to somewhat famously in the SEO world to declare the tag dead, since it was no longer a major ranking factor for even Inktomi: Traffick.com’s Andrew Goodman wrote recently in an essay about meta tags, “If somebody would just declare the end of the metatag era, full stop, it would make it easier on everyone.” I’m happy to oblige, at least in the case of the meta keywords tag. Now supported by only one major crawler-based search engine — Inktomi — the value of adding meta keywords tags to pages seems little worth the time. In my opinion, the meta keywords tag is dead, dead, dead. And like Andrew, good riddance, I say! Since that time, Inktomi was rolled up into Yahoo, which continues to support the meta keywords tag as part of its Yahoo search engine. Or does it? Search Engine Rep Confusion Last month, I moderated my last “Meet The Crawlers” panel for the Search Engine Strategies conference series (Goodbye Search Engine Strategies! explains more about my shift from SES to my own SMX: Search Marketing Expo series). That perennial favorite question came up during the session. Who supports the meta keywords tag? Sigh. But if this question still coming up wasn’t depressing enough, then the search engine reps starting responding with a load of confusion. To paraphrase: No, we don’t support it. Well, we read it. We read it, but it doesn’t matter. Actually, maybe we don’t read it. Even Evan Roseman from Google said at one point that Google reads the meta keywords tag, suggesting no doubt to some that Google uses the tag. To be clear, Google doesn’t. I’ll prove it further below, but it doesn’t, OK? I gave Evan (hopefully) some good humored hassle afterward for saying this. He’s at least the second Google rep to declare this on panels I’ve moderated in as many years, and the problem is that the engineers (from any of the search engines) often take the question too literally. Indexing Versus Retri Versus Ranking To understand, let me talk about three different things a search engine does when it crawls and lists your page: Indexing: This is where the search engine effectively makes a copy of your page. The search engine is going to read and store the HTML content it finds — all of it. Evan was right when he said that the meta keyword tag is indexed by Google. Google knows that the tag exists and has recorded what’s in it. But that doesn’t mean it does anything else with it. Back to my panel experience. Since the reps were unclear, I declared to the audience that I’d just go out and test it again myself. It’s literally been about five years since I’ve last tested the tag, because I (and many others) feel it is so useless. There are better things to do with our time. But since that question needs a big old stake to the heart, I rolled up my sleeves and got cracking. On the Search Engine Land home page, I inserted this meta keywords tag: <meta name=”keywords” content=”qiskodslajdmnkd, ddakaieciuaj jkdalladpaoaw, wdaopeqndlkakljad” /> I had searched for all of these words on the four major search engines of Google, Yahoo, Microsoft and Ask and found no pages that matched. If these search engines made use of the meta keywords tag, I’d know in short order, if my page started coming up. The tag went up on August 28. I then needed to wait until I could see each search engine had the most current version of my page (Squeezing The Search Loaf: Finding Search Engine Freshness & Crawl Dates explains more on how to do this). Google: No It took two days, until August 30, for Google to show the latest version of my page in its index. I searched for each of the words, and my home page didn’t come up. The meta keyword tag was not used for retri and thus not supported. Microsoft Live: No It took five days, until September 2, for Microsoft to show a version of my page with the meta keywords tag on it. As an aside, Microsoft is kind of annoying. It will say something like this in the cached copy of the page: This is a version of http://searchengineland.com/ as it looked when our crawler examined the site on 9/2/2007. The page you see below is the version in our index that was used to rank this page in the results to your recent query. This is not necessarily the most recent version of the page – to see the most recent version of this page, visit the page on the web. If you glance quickly at the date, you might think the page has been revisited fairly recently. But as the text explains, it might be older. Indeed, when I looked on September 2 (as is the case today), the copy of the page in the index was as of August 30, as I could tell from the stories shown. This article comes from： http://searchengineland.com/meta-keywords-tag-101-how-to-legally-hide-words-on-your-pages-for-search-engines-12099 Thanks 2009年10月31日2:02:58 ------------------------------------------------------- 咖啡以外 转载自 文老师博客、Meta KeywordsTag101: How To “Legally” Hide Words |
