Telephony, computers, linked and synchronized accounts: what can we know about individuals today?
Browse the web, have access to social networks, use applications … our daily browsing leaves traces. By crossing this data, it is possible to establish a very precise profile of the Internet user.
What is this information and what does it reveal about our private life? Where are they going What are they used for?
On the internet, each of our actions creates a multitude of data
Places and traces
A lot of data can be found in the history of research cookies (these bits of programs that trace navigation), l 'activity on social networks (“Likes”, status, relationships, music listened to, shared content and metadata contained in the photos providing information on travel) and no need to open e-mails from a mailbox to define the profile of its owner.
The Internet user can also be tracked geographically using the geolocation tool. Associated with Google Map Google can know everything about the movement and habits of the person wearing the smartphone.
When downloading applications it is often asked to synchronize them with the phone. A simple “lamp” application can access the geographic position of the wearer, or scan and share e-mails and contacts.
Voice is also personal data and voice assistants more and more widespread are also subject to data collection.
A precise profile is born from the crossing of data
Cross data a single source can tell us a lot about a user's profile. The metadata of the emails is sufficient to indicate the gender, age, interests, lifestyle, people contacted most often … Same on Facebook which can detect the emotional charge of our messages and deduce the types of relationships maintained.
Now cross even just three datasets. For example, geolocation, email metadata and internet searches. The user's analysis becomes extremely fine: consumption habits, the link maintained between the people contacted, political opinions, religious beliefs, state of health, sexual orientation, ethnic origin, data banking, criminal record … To give a little overview, The University of Cambridge has developed a tool that crosses data from Facebook, Twitter and Linkedin and which offers a psychological profile by following.  Although the challenges of data collection have been known for several years, few Internet users are really aware of it. This video, published in 2015, illustrates the problems well:
When Facebook bought Whatsapp, Instagram and Messenger, and its owner Mark Zuckerberg said he wanted to merge them, concerns arose. These messaging applications have 2.6 billion users and would result in a single user database. This represents a colossal amount of data to cross to better understand the users.
For businesses, capture the data to better act on the Internet user … but not always for their own good
The user experience
Capturing and analyzing data first serves to make the user experience simpler and tends to simplify daily tasks . No more time wasted, the information given on Google's search engines or the Facebook news feed is targeted and adapted to the user. This also serves to guarantee an increasingly refined “personalized experience”. Having access to user data allows companies to offer the most suitable products and content and, therefore, more effective advertising services. 80% of Internet users favor companies that offer hyper-personalized services .
Disregard for privacy and discrimination: when cross-referencing of data puts individual freedoms at stake
Who says targeted data, says filtered data. For a search, a whole section of information risks being put aside if the algorithm considers that they do not conform to the profile of the Internet user. Targeted data tends to shut down internet users in their tastes, knowledge and habits.
This also raises the question of intrusion into privacy. Difficult to know precisely where all this data goes and what uses are made of it. The fields of application are vast and these are sold and traded in an opaque way to commercial companies (bank, insurers, telephony), but also to unknown companies.
Le New York Times  discovered that Facebook has given access to user data to more than 150 companies including Apple, Netflix, Spotify, Amazon and Yahoo !. Could this data have been used for other purposes, such as the Cambridge Analytica scandal?
Tomorrow, the “Data Hub” plans to centralize all digital data. What should we think of this centralization? The computing power of artificial intelligence will multiply the relationships between data. Could a bank loan or a medical operation be refused because of this data? Can we see a generalization of “social credit” based on the cross-checking of data like that in progress in China?
Today, it is essential to become aware of the immensity of the traces left on the internet and what it says about their owner to anticipate possible future uses.
But don't panic, many tools are available to regain control . It is possible to configure your accounts surf anonymously (private browsing or VPN), delete cookies from third parties (with cleaning tools), use privacy extensions / add-ons (HTTPS Everywhere or Privacy Badger) or privatize their searches (using a search engine like DuckDuckGo for example).