How private is your Gmail, and should you switch?

You might be surprised how much Google's email service - and others - know about you. Here's how to set some boundaries

Most people are aware of the cookies that track them across the web, and the privacy-invading practices of Google search, but did you know Google's email service, Gmail, collects large amounts of data too?

This was recently put into stark focus for iPhone users when Gmail published its app privacy label" - a self-declared breakdown of the data it collects and shares with advertisers as part of a new stipulation on the Apple App Store.