How much information about you is on the internet?

It’s often said footprints left on the moon will stay there forever because there’s no wind to erase them.

Similar sentiments could be applied to the digital footprints we indiscriminately scatter across cyberspace.

Every browser search, mouse-click, app login and ecommerce transaction is saved, collated and parsed for any nuggets of information anonymous third parties can glean about you.

That’s why you can spend weeks being shown sidebar webpage adverts for a product you Googled once, or receive spam emails which are curiously relevant to your interests.

It’s impossible to precisely calculate how much personally identifiable information (PII).about you is on the internet, but there are some ways to investigate.

The results are often sobering – and potentially even frightening.

A mouse took a stroll through the deep, dark wood

The first problem you encounter when trying to identify personal data online is that the surface web is only one of three internets.

Beneath the World Wide Web visible in web browsers like Chrome and Safari lurk two parallel universes – the Deep Web and the Dark Web.

We’ve previously discussed in detail the differences between these two oceans of content.

In essence, neither is visible through Google or Bing, which means you’ll struggle to mouse-click your way to personal data repositories on either.

The Deep Web includes everything from corporate databases and archived websites on the Wayback Machine to firewalled content which requires login credentials to be viewed.

The Dark Web is exclusively accessible through the Tor browser. Consumers are unlikely to leave many strands of digital DNA here, and it’ll be near-impossible to find them anyway.

However, there are steps you can take to determine roughly how much content is stored on the Deep Web.

Scroll through your browser Bookmarks. Every website listed will probably have your login credentials, basic account details and contact information saved on its databases.

Next, think about sites you used to frequent – bulletin boards, ecommerce portals, advice forums – which will have retained data from years (and even decades) ago.

How many lapsed subscriptions and policies have you had? How many financial firms may have retained data after you closed accounts? Did you deactivate or permanently delete old listings?

Consider social media posts – not just recent ones but MySpace and Facebook as well. These might seem archaic nowadays, but they still retain vast troves of PII.

These Deep Web databases will be routinely visited by data brokers – companies building vast compendiums of user data to be resold for sales and marketing purposes.

Caught in a web

It quickly becomes apparent that the surface web is where most accessible user data will be located, often in the guise of cookies (PII tracking tools).

Start by Googling (Bing isn’t very good at this) your name, and explore what comes up beyond the first results page.

Use Google’s online reputation management utility to remove both unwanted content and the search results that could lead other people to this data.

A third Google tool involves creating an alert for your name when it appears in newly uploaded content, allowing you to contact the host platform and request deletion.

You have the right to be forgotten by specific companies and websites/services/platforms you’ve previously registered with, though you’d need to contact each one individually.

A more efficient alternative might be to employ a data deletion specialist like DeleteMe. This could become expensive, while some sites are more focused on businesses than individuals.

Accessing the internet through a VPN or the aforementioned Tor browser avoids generating digital footprints. Yet as soon as you log into a website or app, the cookie trail resumes.

Our best advice is to be privacy-conscious whenever you’re online. Only upload content you’re happy for strangers to see; post under pseudonyms; buy offline where possible.

Website archives mean even deleted data may still be publicly visible many years from now.

Ultimately, surrendering personal data online is the price we all pay to enjoy free website, app and social media usage.