Scrollback plans to monetize using a freemium model, charging for features such as private community discussions and advanced moderation tools.
And certainly, there were no shortage of developers that wished they could charge nothing for the app up front, but then charge for features or upgrades later.
Hive.im, which had its beta launch in October, uses a freemium business model and makes money by charging for features like faster video playback and uncapped download and streaming speeds.
(Yahoo! has recently discontinued some of its programs which charged for features. Reports vary, but some Yahoo! email users have reported this service now available for free. Try it on your account to see).
Online or "cloud" services are often free, with charges for extra features, such as more storage space.
The basic service is free, but Fliggo charges for premium features such as teh ability to serve ads or host Fliggo on your own domain.
In terms of business model, Flourish is free for publicly visible projects and templates, but charges for premium features such as private templates, private projects, user management and support.
Chrysler has always priced its vans aggressively, charging extra for features that others, like Honda, provide as standard equipment.
Mr Vogel points to car companies, which may charge extra for features such as anti-lock brakes and passenger-side airbags, instead of offering them as standard features.
These rich environments have the potential to offer capabilities that bypass the control of the carriers who want to charge fees for features that might otherwise be free.
