Links like these will look something like this:

<a href="index.html" rel="nofollow">Home Page</a>

Page addresses to avoid

Spiders will also ignore pages if they don't like URL (the address needed to find page).

For example, a Web site that has URLs containing several variables can cause spiders to ignore page content. You can spot pages like these as they have a ? in them, and &, for instance:

http://webpositioningcentre.co.uk/index.php?page=12&cat=23&jib=c

This URL has three variables, parts with = in them, between ? and &s. We find that if a page has one variable, or even two, top search engines will spider them without any problems. But if a URL has more than that, often search engines will not spider them.

Spiders particularly avoid URLs that look like they have 'session IDs' in them. They look something like this:

http://webpositioningcentre.co.uk/index.php?page=12&id=29c8d7r2398jk27897a8

The set of numbers and letters do not make much sense to humans, but some Web sites use them to keep track of who you are, as you click through their Web site.

Spiders will generally avoid URLs with Session IDs in them, so if your Web site has them, you need to talk to people who developed site about re-writing it so they do not use these IDs, or at least that you can get around Web site without them.

Clean links = happy spiders

If you use clean, easy to follow links without several variables in them, your Web site should be spidered without problem. There are, of course, many other facets to successful Search Engine Optimization, but if search engines can't spider your content, your site will fall at first hurdle.

Latent semantic indexing can help overcome "vocabulary mismatch" problem when a human uses a search engine. Individual words do not always provide reliable evidence about conceptual meaning of a document. For instance, a Web page that is highly relevant to term "laptop" may never use term "notebook," however it is clear to a human being that "notebook" is often used as a synonym for "laptop."

While it is beyond scope of this article to discuss mathematics behind LSI, its implications for search algorithms are simple. LSI can use statistical techniques to create a semantic analysis for any given query topic. In practice, this means that a page can be considered relevant for a particular keyword, even if it does not contain that keyword. For instance, a page that is considered relevant for "laptop" can also be considered relevant for "notebook" even if it does not contain word "notebook," if LSI determines that "notebook" is semantically related to "laptop."

The principle can be applied to backlinks as well. Backlinks with anchor text that do not contain your Web site's main keyword, but instead contain a synonym or related word, may still be giving your site a bonus for main keyword.

Link Popularity Building Best Practice: Vary Your Anchor Text

The recent increase in penalties given to sites with unnatural backlink anchor text, along with possible implementation of LSI, should give webmasters motivation to vary their backlink anchor text heavily. Rather than seeking to only obtain links using their main keyword, webmasters should include synonyms, variations and related words. Certainly no single keyword variation should be used majority of time; rather, text of all links should vary widely, just as they would if links were obtained passively. This will ensure a site's improvement in SERPs, without drawing a penalty flag.