These day many (if not most) people use facebook with a mobile browser or app. Mobile facebook users who click on an url pointing to a tab page will get an error message, saying they cannot view the page. Not only is that a bad user experience, it is also loss of a potential fan or customer.
A solution would be something like tabsite offers:
It would be great if fanpage builder had something like that built in, and preferably with the mobile version of the page hosted on our own site, allowing visitors to continue browsing our own site.
*Page should look and behave like a facebook tab page, including facebook buttons, likegate, etc.
*Might require a dedicated theme on a subdomain, or on the homepage using a themeswitcher, or display in a frame/div/modal/whatever
*If possible use a facebook url to the tab page, as people may be more inclined to click such a link (I know facebook apps can be used for redirecting, but no idea if it can be used for a brower-based redirect)
A feature like this would be a great selling point for fan page builder!
Here's how to do the redirect through facebook: