It’s a well-trodden rumor, but Facebook is reportedly testing a new “Want” button plugin, which would mirror its popular “Like” button, but appeal more to the
company’s ecommerce ambitions. Developer Tom Waddington from Cut Out + Keep apparently discovered that a Want button has been added to the Facebook Javascript SDK as an XFBML tag --
<fb:wants>. “The button is not publicly listed among the other social plugins on Facebook’s developer site,” Inside Facebook notes.