HU have just let us know that people can now opt out of being followed by other people.
You need to click on the down arrow next to your name on the green bar, then on 'account'.
If you scroll down you will see the option 'Allow other users to follow me' with a tick box. If you untick this, people will not be able to follow you.
As far as we know, this will NOT stop people being able to follow posts that you have posted.
I'm afraid I have no idea how you would achieve this on a smart phone or tablet.
I know that some of you were not comfortable with the idea of someone following you, so for some, this will come as a relief.
Please bear in mind that you permanently lose all your followers if you disable it.