Okay, let me clarify a little.
Sure, boycotting companies who's policies disagree with you might have some effect if done on a large scale, but what troubles me is people who believe that doing so can substitute for real political consciousness. In a consumer culture like ours, it is very easy to do so. And the corporations love it when we think this way.
Take for instance
this advertising campaign, and
many others from the same source which is so over-the-top disgustingly saccharine as to almost serve as a parody of the style of corporate propaganda I am speaking about. Corporations have being going off at the hip about how eco-friendly and otherwise positive they are in the world for some time now, because they realize that it can make money for them. Look at Google's ludicrous "don't be evil" motto, and realize Google is probably one of the most evil corporations out there ...
Back to our hippie toothpaste. Now realize that Tom's of Maine is a fully owned subsidiary of
the Colgate-Palmolive company, which is where, presumably, this former small hippie-owned business got the loot to engage in the above sleek advertising campaign. Buy Tom's of maine, and sure, it may be natural, the subdivision of the corporation that you are buying from might have some smiley-face policies, but ultimately, you are still giving your money to a big fuck-off corporation.
Of course this is not entirely analogous to your situation, but it serves to illustrate one instance of corporate America utilizing the type of attitude I'm describing, "what I buy defines me," e.g. "if I buy all-naturally/locally-sourced/eco-friendly/whatever schwag then I am making a meaningful difference in the world," or it's inverse, "if I refrain from buying things which are not {
whatever}, I help make a difference in stamping out {
whatever}." If you buy into this philosophy sufficiently enough, you abdicate your responsibility to really think deeply about politics or act in a meaningful way, and you play right into the hand of the corporatists. They are not threatened by you taking your few dollars one place or another. In fact, they'd love you to do so, if it means that you don't actually go any deeper with your political activity than that. It's all a ruse. It lets you feel like you are being socially conscious when really you're just another consumer, defined by what you counsume, pacified by media, and not thinking an original thought in your life.
(Now is that you? I don't know. This isn't a political thread, I don't really know in detail your politics. But noddy's post above is well-taken too, to one extent or another.)