(Download page: PR Block)

zem_prblock reduces the incentive for comment spam by blocking PageRank on outgoing links.

Comment spam is usually motivated by web site owners trying to improve their ranking in Google search results. They do this by including links to their web site in comments submitted to many different blogs. Google interprets these links as meaning that the spammer’s web site is very popular.

zem_prblock works by ensuring that Google ignores links to external web sites. It offers two different methods: javascript redirection, and the rumoured-soon-to-be-announced rel=nofollow technique. The plugin only effects links within a predefined block, and skips local, relative and ‘mailto:’ links. Additionally, it can be used to apply predefined attributes to offsite links, for example to force external links to open in a new window, or to display them in a different colour.

To use it, edit the Textpattern form named comments (not ‘comment_form’ – that’s the input form), and surround the code with a <txp:zem_prblock> </txp:zem_prblock> tag, like this:


<txp:zem_prblock>
<txp:message /><br />
<small>&#8212; <txp:comment_name /> &#160;&#160; <txp:comment_time /> &#160;&#160; <txp:comment_permlink>#</txp:comment_permlink></small>
</txp:zem_prblock>


The tag can also be used in other places, such as an article form, but the benefits are most obvious when used to block links submitted in comments.

Attributes:

• type – Use type="javascript" to replace links with Javascript redirection; or type="nofollow" to add the rel="nofollow" attribute. The default is ‘nofollow’.
• class, target, etc – These and any other attributes (with the exception of type) will be added to off-site links, overriding the existing link attribute if it was set. Local and non-http links will not be changed. For example, this will add target="_blank" to all external links in an article body:


<txp:zem_prblock target="_blank">
<txp:body />
</txp:zem_prblock>