Robot and Spider Control
Editor’s note: Search engine spiders are typically the only kind of spiders that Webmasters want to see hanging around. These robots quietly crawl their way around the World Wide Web seeking out every page they can find, and reporting their contents back to their search engine masters. This is usually a welcome operation as it often leads to more ‘free’ traffic – but occasionally robots find their way into places we wish they wouldn’t, exposing sensitive information for the world to see… Here’s how to help prevent this from happening: ~ Stephen
Before submitting your site to the search engines, you will want to consider what pages and links you want the search engine "robot" (the program that indexes your site) to "spider" (follow), and what pages you don’t want it to follow – since you may have pages with sensitive information, a ‘scrap directory’ full of "work in progress," or a protected "members area" that you would not like listed.
This goal can easily be achieved in two ways. The first way is with a robots.txt file placed in the root directory of your Website, but you must have full domain privileges in order for this to work. While this article is not meant to deal with the intricacies of the robots.txt file, a quick word of warning is in order: never leave this file empty, as it will indicate to some robots that you do not want any part of your site indexed.
The other way to stop most ‘bots’ from searching or indexing your page is to use META exclusion tags. This is often the only way that Webmasters on virtual or free hosts without full server access can hope to control a spider’s wanderings and reports on a page-by-page basis. The syntax is simple:
<META name="ROBOTS" content="ALL,NONE,INDEX,FOLLOW,NOINDEX,NOFOLLOW">
The default value for the robots tag is "ALL" which allows the robot to index the page, then spider all links, indexing the linked pages too. "NONE" performs the opposite, disallowing the robot from either indexing the page, or spidering the links on it, in essence ignoring the page altogether.
"INDEX" indicates that robots should include this page in their search engines, while "FOLLOW" means that robots should follow (spider) the links on this page. Conversely, a value of "NOINDEX" allows links from the page to be spidered, even though the page itself is not indexed, while a value of "NOFOLLOW" allows the page to be indexed, but no links from the page are to be spidered.
Some Sample Snippets
Here’s some example robot controlling META tags, which would be put in between your document’s <HEAD> and </HEAD> tags:
<META name="ROBOTS" content="NOINDEX">
- This will prevent the bot from indexing that page.
<META name="ROBOTS" content="NOFOLLOW">
- This allows the page to be indexed, but any hyperlinks in that page will not be spidered.
<META name="ROBOTS" content="NOINDEX,NOFOLLOW">
- Is a combination of the two, where the page will not be indexed, and other links will not be followed. This tag may also prevent some mirroring software from downloading the page.
While there are many other META tags that can be used to improve your rankings, controlling what’s ranked is the first step, after which it’s wiser to invest your time in optimizing your description and keywords tags in order to boost your search engine rankings, which is the subject of my next article…