Instant messaging, that rat-a-tat chat technology that is catching up toe-mail in popularity, still hasn't overcome a critical hurdle that e-mail cleared years ago: utter incompatibility among rival brands.

FORBES: Instant Headache

"Clearly some supporters feel aggrieved that a song they believe to be no more than a tit-for-tat 'wind up' of Celtic supporters should be singled out in this way and merit the attention of police, governments and anti-racism organisations, " said Bain.

BBC: Bain responds to 'Famine song'

If trade policies are deemed to hurt a tradig partner, a trade war can erupt, in which countries ratchet up protectionist policies in a tit-for-tat manner, ultimately leading to economic slowdown.

FORBES: Eight Biggest Global Trade Offenders