Here’s a cautionary tale for the corporate social media consultants of the world. Last week, McDonald’s launched a Twitter campaign using the hashtag #McDStories; it was hoping that the hashtag would inspire heart-warming stories about Happy Meals. Instead, it attracted snarky tweeps and McDonald’s detractors who turned it into a #bashtag to share their #McDHorrorStories.

When it's done right, Twitter can be a powerful marketing tool. When it's not, it can be a recipe for disaster.

New verb: bashtag. The act of hijacking a publicly-broadcast hashtag. As in: "man, the climatecamp has just been mercilessly bashtagged".