I find both methods to work fantastically, but Svetoslav is right you should diversify the like button. I was running social media on someone else's site so I didn't have the option to play with any of the widgets on the retail site, but I was able to get fantastic conversion on Facebook pages by running the ads to the page and then engaging the audience through there. I easily added 5K-10K new followers per week depending on if I ran an ad to the page or not. Overall sales increased during that time by 30%. Now I work doing content SEO which is hard because I don't actually touch any of the content I mainly have to oversee and hope that people take my suggestions. : /
