It's also really only practically done by organized, well-publicized groups that will actually stick to their guns and follow through with their purchase embargo, and who might have some chance, however slim, of thereby actually effecting change. Anonymous, individual randos stating "I'm boycotting!!!" on random Internet forums usually can't be held to their pledges, because of that anonymity, making these proclamations more or less useless, except for letting the person making such a grandiose proclamation feel important.