Oh, this is so wrong...
Ruby on Rails makes it easy to "do a link via post" : see
Ajaxian: Ruby on Rails uses Ajax to simulate POST links.
This hack is purely to make a button in the user interface not look like a button. The problem is that most of the operations this is intended to be used with are 'remove' or 'delete' type of operations - actions that a user really really should know about ahead of time. More than once I've seen a link for "delete this picture" - just clicking causes the data to go away (Flickr is guilty of this). While I sympathize with a page designer trying for a spartan look and feel, it is important to realize that a link is not a widget. This breaks the explore-ability of Web applications and exposes destructive operations to utilities and tools that pre-fetch data - links should cause no harm.
To really get the job done, Web designers should do the work to define the CSS necessary for a form to fit within their design. Keep links safe - just say no to 'links via post'.