In the future, the internet could come through your lightbulb

My grandfather used to design fairly big radio transmitters. He told a story of walking after dark in the nearest town to a transmitter with a colleague who had been a wireless operator on a ship. The colleague could read the news headlines from the streetlights.

What if I don't need light right now? Can LEDs transmit data at levels a human eye can't see, so as to not irritate us under day light?

Also, could lightbulbs have IR transmitters alongside the ordinary light, again so as to not depend on the visible light?

I've seen a demo of that. I can't remember where at the moment. IIRC they don't need to resort to using IR, they can just use such low intensity of light that it isn't perceptible by people. Not sure if this can currently be accomplished in bright sunlit locations though.

I saw it in TED talk

http://www.ted.com/talks/harald_haas_wireless_data_from_ever...

Year-old : http://thenextweb.com/insider/2014/08/21/purelifi-li-fi-vlc-...

IrDA is a much more recent and relevant example of a similar concept than Bell's photophone. It had a short run before being largely replaced by a radio-frequency technology - Bluetooth.