The UK's Advertising Standards Authority has ruled that Nike broke marketing regulations by having two of its sponsored England footballers tweet as part of an ad campaign. Wayne Rooney and Jack Wilshere both posted messages several months ago with the hashtag #makeitcount and a link to a Nike promotional site, but the ASA decided that the tweets weren't "obviously identifiable" as advertising. Nike has been banned henceforth from running similar campaigns on Twitter.
The ASA's first Twitter case came in March, when it investigated Rooney's Manchester United teammate Rio Ferdinand and reality TV star Katie Price over similar tweets promoting the Snickers chocolate bar. The tweets in question were found to have been obviously identifiable as advertising, however, because Ferdinand and Price both used the hashtag #spon (for "sponsorship"). The Nike decision means that companies marketing products in the UK will have to ensure they're transparent about their Twitter activity going forward.