When linking to your website from Facebook you may find that Facebook automatically changes the URL to the main Shopp catalog page (or a child of that page). For example, if you are typing out a status update or comment and try to link to the following URL:
Facebook may automatically convert this to:
When Facebook detects that you have tried to insert a link it will first scan that web page before the link is embedded. During this process if it comes across a canonical URL declaration it will automatically use that URL in preference to the one actually entered by the user.
<link rel="canonical" href="http://www.mywebsite.com/shop" />
The above element may be found within the
<head> section of the web page (try using your browser’s “View Source” option to determine if this is indeed the problem). If, as in this example, the canonical URL is present but incorrect then that will create problems when linking to the site from Facebook.
These incorrect references to the canonical URL can be generated when using plugins such as the All in One SEO Pack. This is not usually due to a flaw in the plugin but rather is due to poor configuration.
The easiest solution is of course to try disabling your SEO plugin.
Of course, that may not be desirable in which case the configuration of the SEO plugin will need to be changed. Since this process varies according to the specific plugin being used the best advice is to refer to that plugin’s documentation or seek help from it’s author.