As she made the long journey from New York to South Africa, to visit family during the holidays in 2013, Justine Sacco, 30 years old and the senior director of corporate communications at IAC, began tweeting acerbic little jokes about the indignities of travel.

As couples celebrate the most romantic day of the year, those looking for love online have been given a reminder they are courting a “virtual” stranger who may not be all they seem.

Mila Kunis has "never" dated.