When using someone's Wi-Fi, what can they see?

When you use someone's Wi-Fi, you're on the honour system.

If you want to visit their home and use their network, they can say "yes, okay," but you might not always get a welcome.

What they see is a matter of policy. It depends who you are and what your device supports. Some apps can let people see what you've been doing online in the past on their network. If you're the visitor and not the person giving the tour, you may have no idea how it works.

WIRED OPINION. James Temperton (@jtemperton) is head of the Digital Infrastructure and Technology team at the British Library. Previously, he led the BBC's digital strategy and managed the development of the World Wide Web for TV.

The BBC has a long history of developing web technologies, and has worked on many security issues as well. In the late 1990s, the BBC published a paper setting out its vision for web standards for video, audio, and data delivery (though it didn't reach a conclusion about these technologies). There was a clear view that the BBC could influence standards for multimedia on the web, and in recent years, there have been efforts by the British Government, National Health Service, and major telecommunications companies to develop Open Platform for Health and Open Platform for Healthcare Data. The UK Research Council, the Department of Health, and other government agencies also have a mandate to support open source software, which is being delivered using cloud computing. The BBC has worked with these projects as well as others. One of the other big challenges we face is that, as a public service broadcaster, if we make any effort at all to promote our own applications or services on the web, we have to accept that people may use them for bad purposes, too. But there are ways to limit the impact of misuse in terms of both privacy and copyright. That's a problem for us, but I'm pretty sure that it is not the major concern of the average householder. You cannot really blame a householder for not understanding and knowing about their rights, or how their ISP handles the traffic leaving their home.

Wi-Fi is also a relatively new phenomenon. For much of the last century, radio signals were received in homes, but not processed, recorded, or analysed. The first commercial Internet Service Provider, AOL, did not launch until 1996. There are many challenges around secure Wi-Fi.

Can a Wi-Fi provider see your texts?

When you walk into a restaurant or shop, you enter a "shared" space -- someone else's property that you have permission to use.

Sharing is a basic part of life in the digital age. We share our photos, videos and music; we talk on Skype and listen to Pandora. And we share our data, too: your Wi-Fi information, your Netflix viewing habits, even how much money you spend on a given day.

But it wasn't always this way. Sharing was largely done manually, by swapping out physical keys or USB sticks. It was done online, over the telephone or via email. The process was relatively slow and manual, with a lot of effort involved in setting things up and sharing the data.

It was the rise of the smartphone that put a wrench in those plans. Our phones are fast, responsive and capable of sharing data in an instant, almost anywhere. Suddenly, we could take our photos and videos and upload them for others to see or hear -- all through the wireless network in the restaurant, at Starbucks or in the office.

The smartphone changed the idea of sharing from a manual, labor-intensive process to one that is largely automated and instantaneous. But one small problem has emerged: How do we share that data? The problem is that, in the past, people had to actively share their data. They had to say, "Here's my Netflix password," or "I'm sharing my Wi-Fi information," or "I'm ready for you to see this."

Now, those conversations have largely been replaced by new technology. Smartphone users can share data automatically without saying a word, as long as they're connected to a wireless network.

"This is our vision: to completely automate sharing of the things that we share online," said Paul Bressler, chief technologist at the Wi-Fi Alliance. In other words, as long as we're connected, our smartphones will be sharing some of our data without us knowing it. It's not what we've always done, but it's a new way of sharing. And it's happening with our eyes closed.

Sharing through networks and apps. The way you share data online has changed significantly over the past few years. First, companies started building ways to get people online faster -- and to bring content to people.

Can people see my history if I use their Wi-Fi?

Wi-Fi at the airport is free, but many hotels charge a monthly fee for Wi-Fi.

If you want to browse the web and send e-mails without a data plan, you could set up an account with one of the many free Wi-Fi hotspots around the world. And if you really want to stay off the grid, consider using your phone's 3G data service when in the country of interest.

Read also: You can see what you did on Wi-Fi if you're sharing an open network with others, so it's best not to publicly connect unless you want people tracking your browsing history. You might also be exposing yourself to malicious hacking attempts.

There's a lot of useful information online about Wi-Fi security, including information about how you can limit your exposure to this kind of hacking. But if you really want to avoid any security problems, it's probably best to not use unsecured Wi-Fi in the first place.