First, the good folks at Twitter must take down imposter sites - and not just ones purporting to speak on behalf of a company. Not to do so is potentially damaging for both Twitter and the people and organisations being impersonated.
Second, PR practitioners have a duty to protect their clients and employers by looking out for imposter sites and by developing credible and trusted communications that use the new technology tools wisely. The recently updated CIPR social media best practice guidelines are a good source of help. Go to www.cipr.co.uk/socialmedia.
Kevin Taylor, president, CIPR