If you have ever stayed in a hotel, used Wi-Fi on the London Underground via a specific supplier, or been at an event with 'free' Wi-Fi, you've possibly had to hand over details about yourself before being allowed to surf the web and check emails, etc.
Free Wi-Fi is often a genuine 'no strings' perk when staying as a guest in a hotel etc., but often, the offer of 'free' Wi-Fi comes with a catch... you have to give the service provider or hosts something in return. Normally, the only thing they want is your email address and sometimes a little detail about you. We noticed recently that if you sign up for free Wi-Fi access at one of the smaller West Country domestic airports, you are prompted to join their mailing list too. The airport would then know something about you; your email address (obviously), and the fact you used the airport to travel on a particular date.
This may seem like very limited information, but data is king. The more data a company holds about you, the more effective their marketing to you will be. For example, if an airport could establish a pattern for your travel (let's say you always log in on the last Friday of every month), they could use this information to target you with special offers around that time of the month. Or perhaps encourage you to visit a particular concession at the airport for your next visit.
The key to building these data profiles is by not asking too much of those who may want to sign up. If users feel they have to sacrifice too much personal information, they won't agree. So, service providers often go for the little by little approach and often track your 'journey' through their databases until you make another booking or have another interaction with them. By matching up your email address etc. from a free Wi-Fi sign up, a company could cross-reference against email addresses used to make a future purchase.
Moreover, if you interact with any of the marketing targeted against you but then don't make a purchase or interaction any further, you may be 'retargeted'. Internet search engines can actually use uploaded lists of email addresses from advertisers to use in retargeting campaigns. This means advertisers can use your email address to identify you to the search engine (when you are logged in) and thus you can be targeted with very specific information. For example, if you used that free airport Wi-Fi, the airport could upload your email details to the search engine and then, when the search sees you're logged in and using their channels, they could serve you an ad about that airport. This is very targeted marketing and is proven to deliver significantly better results and Return on Investment (ROI) than cold generic marketing.
So, if your business operates Wi-Fi, or already provide Wi-Fi access to visitors at your place of work, think about how you can ethically use the data you have collected to legally target, retarget, and promote brand awareness. From a technical perspective, your biggest obstacle will be where there is good 3G or 4G connectivity as users would have much less of a need to log onto Wi-Fi where decent operator network connections exist.