The BBC reports: Brazilians are among the world's biggest fans of Twitter. Now the microblogging site has become the setting for a battle of wits between police and residents of Rio de Janeiro over a drink-driving campaign known as Operation Lei Seca, or "dry law". Anyone who has had too many beers but wants to drive home can turn to a page on Twitter, where those who have seen the distinctive branded police vans warn others which routes to avoid. LeiSecaRJ has been nominated for Twitter's Shorty awards 2011, an annual event honouring the best producers of short, real-time content.