If you are a webmaster, chances are you have spent time looking for other sites with which to link.
Did you know that many webmasters out there go out of their way to hide your link from the search engines in order to boost their own rankings? If you already know this, then you probably already know about the techniques employed to make certain your link to their site gets counted with the search engines and yours doesn't.
However if this sounds new to you then you really should read on.
So what are the techniques they use to get an inbound link without reciprocating or by devaluing the link so much that it is worthless?

• Multiple links into different sites for a single link out from a central directory
• Links into sub domains
• JavaScript wraps
• Blocking search engine spiders using Robots.
  txt
• Using META tags to block the search bots
• Orphan link directories

Reciprocal and Inbound Linking Despite announcements to the contrary, reciprocal linking is not dead yet.
The premise is a simple one: I'll link to you if you link to me.
What could go wrong with such a simple arrangement? Inbound links.
Some webmasters salivate at the thought of a bunch of juicy one-way, inbound links to their site.
All the sweeter if they have gamed another webmaster into giving them one by promising reciprocal linking but hiding their link from the search engines.
Since a one-way, inbound link is generally given more weight by a Search Engine, webmasters do what they can to develop inbound links, for example, offering free web tools or by writing articles like this one.
Checking for the Scammers Sometimes this is obvious and sometimes a little digging is required.
I often use http://www.
linkmarket.
net to help generate links and will manually check every site I consider exchanging links with using the following criteria:

• Check the link page is there.
  It is surprising how often the link page doesn't actually exist!
• Is the site a sub-domain? Personally, I don't like to reciprocally link to sub-domains because they typically use a central site directory.
  In other words, you will provide multiple links into a site using sub-domains but only receive a single link back from the central link directory.
  
• Is there a link to the homepage from the link page? If there isn't, the chances are the link page is an orphan page or a central link directory for a number of sites.
  An orphan page is invisible to the search engines while a central directory provides a single link out for multiple links in and may not even be visible to the SE's at all.
  
• Can the link pages be found from the home page? Again, unless your link appears on a page that is visible to the search engines it is pointless exchanging links.
  Webmasters trying to game the reciprocal link system will set up a link directory but will not actually link to it from the main body of the site; in effect preventing the search engine spiders from 'seeing' it.
  
• Is the link a standard text link or is it wrapped in JavaScript or using a php server-side include? JavaScript wraps are a common way of hiding a link from the search engine spiders whilst giving the appearance of being a normal text link.
  PHP or other server-side includes are also sometimes used to disguise links.
  
• Does the Robots.
  txt file exclude the search engines from spidering the link pages? A quick check of the Robots.
  txt file will soon tell you if the SE's are excluded from the links section.
  
• Are there META tags in place to prevent the SE spiders from following the links? Some webmasters will place the NOFOLLOW or NOINDEX attribute in the META tags on link pages.
  
• The rel="nofollow" attribute applied to "a href= links".
  A way of fighting comment spam in blogs, this attribute is also being used to prevent SE spiders from following the links.
  

Luckily, Firefox has some useful extensions to assist with these tasks.
Chris Pederick's Web Developer toolbar (http://chrispederick.
com/work/webdeveloper/) and Quirk's Search Status toolbar (http://www.
quirk.
co.
za/searchstatus/) are two excellent additions to a webmaster's kit that allow quick access to the information.
A Brief Word About PR (Page Rank) Don't assume that because a page is showing zero PR (Page Rank) that it is being hidden from the search engines.
PR updates are irregular and take time to filter through to the lower site pages.
Although zero PR may indicate sneaky linking practices, this is not always the case so it is worth checking just to be sure.
There are lots of webmasters out there who are eagerly seeking links with like-minded individuals who run websites with a proper approach to reciprocal linking.
By adopting a more rigorous approach to examining the sites you intend to link with, the bad apples can be avoided and the good sites rewarded, which is as it should be.