Witnessing friends' vacations, love lives and work successes on Facebook can cause envy and trigger feelings of misery and loneliness, according to German researchers.

Facebook was by far the biggest offender, with 66 per cent of lawyers citing it as the primary source of evidence in a divorce case. MySpace followed with 15 per cent, Twitter at 5 per cent and other choices lumped together at 14 per cent.

A study says that offline socializing brings more happiness than online. Offline socializing means meeting real people, spending time with family and friends, and talking to them in person instead of texting, emailing them, or checking their status updates on social networks.