Users can opt in and out of advertisements at any time.

Some users opt to make their profiles available for everyone on Hi5 to view.

So users can opt out of having Amazon essentially being a man in the middle.

Users can opt to view the same pictures as their friends in real-time.

The number of classes is five unless the user opts to change this value.

The user could also opt for news updates from the service provider.

Most regular users of the technology opt to purchase it outright.

Users of a new car stereo may opt to bring it inside every night, but not just to prevent theft.

If personal information is going to be used for promotion, marketing, research or any other secondary purpose, our users must "opt in".

Users may opt to "pin" programs to this side of the Start menu so that they are always accessible.