The concept itself is actually a good one; it's just named wrong. Had they called it "follow" or "subscribe", or even the old name "become a fan", it would have been much clearer.
They do give you the choice to display the button as "Recommend" instead.
In my opinion, both "Like" and "Recommend" would be perfectly suitable names for this feature were it not for the ability of those pages to post to your feed thereafter. I think that socially, it's a genuinely good feature.
