I rather like O2's approach to social media. On their Twitter account if a twittering twat says "i hatez u o2 c**t" or suchlike, their usual response is "we're crying, sad face". Granted, not particularly helpful, but an appropriate response.
On the subject of EE, whilst deleting posts is unforgivable wanting customers to private message them with personal details and mobile number seems quite sensible rather than plastering them on a public forum.