Whilst originally designed as a way for people to buy secret presents for their partners or to Google things they were too embarrassed for anyone to know, incognito windows are used by a vast array of people to watch porn.

Yes, Google Chrome’s incognito mode allows you to browse porn to your heart’s content and your laptop or phone will store no evidence of it.

And it appears the brains behind Google are well aware of the function’s main use.

Porn audio plays in US supermarket

When you open 100 incognito windows, a smiley or winky face appears.

Instead of the normal tab counter in the top right-hand corner, users will see the cheeky face.

A winky face - ;) - appears on Android devices, whereas iOS users see a normal smiley - :).

Google seem to be poking fun at prolific users of incognito windows but it’s unclear why the faces appear.

(Google (Google)

According to Mashable, it could be that the app wasn’t designed to have more than two characters in the number of tabs field so rather than displaying three digits, they use a face instead.

This is just one of many hidden features - known as Easter Eggs - in Google Chrome.

For example, if you search ‘google in 1998’ in your browser, you’ll be transported back to the original version of the search engine.

Another fun secret trick is a game you can play when a page is taking a while to load - press the spacebar and a dinosaur will appear.

You then use the spacebar to make him dodge obstacles.