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Filter bubbles in internet search engines

22 June 2011 Last updated at 10:57 BST

An internet expert has published research saying we are all living in "filter bubbles", whereby corporations decide what each individual sees on the internet.

Eli Pariser says that companies monitor our behaviour and interests and give us corresponding search results even when we do not realise it.

Rory Cellan-Jones has tested the theory for Newsnight.