There are more wireless hotspots in the UK than anywhere else in the world except Ireland.
Richard Westcott's been investigating your worries
That's great if you want to connect to the internet on the move, whether by laptop or mobile phone.
But, although the scientists say the technology's perfectly safe, some people believe it's making them ill.
This morning on Breakfast:
Our business reporter Richard Westcott has been investigating their worries.
He talked to one woman, who believes that the electromagnetic radiation generated by wi-fi is making her ill. She's using special insulating wallpaper and a detector, to keep her symptoms under control.
And he also talked to a government scientific adviser, Dr Michael Clark, who's sceptical that wi-fi can really make you ill.