The idea is that, with the constitution adopted, Serbia will hold an election before Kosovo goes, stopping the extremist Radical Party from picking up more disaffected votes.

ECONOMIST: Serbia and Kosovo

They can also trade weapons and other assets, offer advice, or pressure someone into picking a fight with a third party.

ECONOMIST: Computer games

In the past, Twitter has taken flack for cherry-picking product features from other third-party developers or just acquiring certain developers that make those features.

FORBES: Twitter Investor Defends New 'Tweet' Usage Rules