This question can reference two separate ideas. First, in what ways is your news personalised, and second, what are the mechanics of all that. We thought we'd answer both questions in one post.
In what ways is your news personalised to you?
We personalise your news implicitly and explicitly. Explicitly, you choose filters, search terms, and watchlists, then we ferret out the most relevant news with those things in mind. We even give you a CityFALCON score so you know just how relevant that article or tweet is to your current needs. You can also choose a market segment that is most relevant to you, such as daytrader or corporate treasury (employee), and we provide news specifically tailored to that group of people.
Implicitly, we also look at the stories you've liked, you've disliked, and how other people have reacted to that same content. We even look at how long you view a page or whether you consistently prefer one author or source over another. A lot of this is unconscious or it might be hard to view from outside your own perspective. We use this kind of data to understand you, your interests, and your goals so we can provide a better experience.
What are the mechanisms for personalisation?
We track lots of things like time-on-site, number of clicks on specific sources or authors, what your watchlists are, whether you are searching individual terms or using watchlists more. We even look at things like which page you enter the site on or how fast you leave. These datapoints are stored in our databases and sent to machine learning algorithms to seamlessly deliver a better experience. For the most part, you don't even know it's happening.
This does open up some privacy questions. We strongly believe in privacy, and because of that, we do not use any of the data we collect for any purpose other than providing a better experience. We don't sell or give away your data to third parties, and we even store everything on our own servers so we have full control and no one else. Driven by self-preservation, we don't want to run afoul of GDPR and other privacy laws, so we're quite serious about privacy. Driven by our own humanity, we don't want to run afoul of the Golden Rule, and we wouldn't want anyone selling our information.