It's disappointing, but to be honest, not all that unexpected. A company blocking links to competitors on their service is pretty common, even in the world of social media and instant messaging.<p>Which raises an interesting point with these services. At what point is it 'wrong' for a company to control what people can link to on their service? This example is pretty tame given it's merely not being linked, but if the link had been removed altogether, would that be 'unethical'?