Rather than adding journaling as an add-on feature like in the ext3 file system, it was implemented from the start.

Still, Yahoo does sell a significant number of add-on features to users of its free service.

Providers frequently offer add-on features for conference calls, such as:

For users, they are still expensive add-on features and come with their own set of integration problems.

Credit scores are available as an add-on feature of the report for a fee.

Moreover, the university insists on having innovative technology as an integrated part of the learning process, and not as an add-on feature.

It was sort of an add-on, upgradeable feature, but wasn't used.

They sometimes include interchangeable lenses and many add-on features, such as external flash units.

Philips plans to sell an add-on feature to create full motion.

Instead, they implemented a payment system, where users can purchase add-on or premium features.