Hyperlinks are the nervous system of a crawler. Crawlers follow these links to determine which pages of your site should be crawled. If your hyperlinks are broken or unusable, this will prevent your pages from being crawled.
- Keep the links on a given page to a reasonable number (fewer than 100).
- Image maps for navigation are also bad. Since the navigation is based on an image, crawlers may not be able to process the links properly, and will not follow them to their referring pages
- Broken links are obviously bad as well. If the link is broken, that page will not be crawled or indexed, and will not be found by your search users. You should check your site with a Link Tester to prevent this from happening.
- The search engines basically figure that if you are linking to something from your page, whatever it is you are linking to is likely to be closely related to the content of your page. For that reason some of the engines actually look for keywords in the hyperlinks and any text immediately surrounding the hyperlinks. What this means to you is that if you can you should include your most important keyword phrases in the link itself and possibly the surrounding text.
- The text of your link should be natural content text, not “click here.” You should also try to incorporating your keywords in your hyperlinks, but do it without being artificial.
- Changing the style of your link with a cascading style sheet will not affect crawling or Page Rank, however blue underlined text is a usability convention that if not used may confuse your users.
- Just as the robots tags can prevent links from being followed, each individual link can do the same, using the rel=nofollow attribute of the link tag.