Google is preparing to test a 1 gigabit broadband service in the US. Just to recap, that’s 1000 megabits per second. Put another way, that’s the theoretical ability to download a DVD in 37 seconds.

The plan is to work in partnership with local and state governments to set-up fiber-optic networks reaching between 50,000 and 500,000 people. One analyst says that each network would cost somewhere between $60 million and $1.6 billion to set up. The scary thing is that that’s effectively loose change for Google, which has approximately $25 billion in cash.

Nobody seems to be able to come up with a logical explanation as to how these projects could possibly be profitable at this stage, though it appears that might not be the intention. Instead one theory has it that Google simply wants to supply ridiculously fast broadband to enough people that they’ll sing its praises and prompt the rest of the population to demand faster speeds from their own providers. The idea is that the faster people can access the internet, the more sites they’ll visit and thus the more adverts they’ll see.

It’s also not clear how and why Google went with the 1 gigabit figure. It would certainly be an amazing coincidence if that really was the maximum speed the proposed networks could reach. More likely the firm either thought it made for an impressive figure or simply liked the fact that it started with a ‘G’ (look out for the term “Googlebit”.)

There is a more sinister possibility though. If Google controls your internet access, it means it has the technical ability to know everything you do online. And for a company that makes its money by selling targeted advertising, that could be a goldmine.

Of course, from the company with the slogan “Don’t Be Evil”, it may be hard to see them use such intrusive tactics. It might be hard to imagine any internet provides using your entire internet activity for advertising, but that’s exactly what a controversial firm named Phorm tries to do and has even tested secretly with some ISPs in the United Kingdom. It may turn out that a loss of privacy is the price to play with ultra-broadband.