paid. The word freemium combines the two aspects of the business model: "free" and "premium". It has become a popular model especially in the antivirus industry. Red Hat Linux OS works in a similar fashion, with a version for free use (Fedora Linux) and charging for their premium Enterprise version. Adware Adware, short for "advertising-supported software", is any software package which automatically renders advertisements in order to generate revenue for its author. Shareware is often packaged with adware to lower the shareware fees or eliminate the need to charge users a fee. The advertisements may take the form of a banner on an application window. The functions may be designed to analyze which websites the user visits and to present advertising pertinent to the types of goods or services featured there. The term is sometimes used to refer to software that displays unwanted advertisements, which typically are more intrusive and may appear as pop-ups, as is the case in most ad-oriented spyware. During the installation of the intended software, the user is presented with a requirement to agree to the terms of click through an end-user license agreement or similar licensing which governs the installation of the software. Crippleware Crippleware has vital features of the program, such as printing or the ability to save files, disabled or unwanted features like watermarks on screencasting and video editing software until the user buys the software. This allows users to take a close look at the features of a program without being able to use it to generate output. The distinction between freemium and crippleware is that an unlicensed freemium program has useful functionality, while crippleware demonstrates its potential but is not useful on its own. Donationware Donationware is a licensing model that supplies fully operational unrestricted software to the user and requests an optional donation be paid to the programmer or a third-party beneficiary (usually a non-profit). The amount of the donation may also be stipulated by the author, or it may be left to the discretion of the user, based on individual perceptions of the software's value. Since donationware comes fully operational (i.e. not crippleware) with payment optional, it is a type of freeware. In some cases, there is a delay to start the program or "nag screen" reminding the user that they haven't donated to the project. This nag feature and/or delayed start is often removed in an update once