Pros and Cons of Plugin Systems

A plug-in (plugin, addin, add-in, addon, add-on or snap-in; but see extension) is a computer program that interacts with a host application (a web browser or an email client, for example) to provide a certain, usually very specific, function “on demand”. Applications support plugins for many reasons. Some of the main reasons include: enabling third-party developers to create capabilities to extend an application, to support features yet unforeseen, to reduce the size of an application, and to separate source code from an application because of incompatible software licenses.

Examples of applications and their plug-ins include:

• Email clients use plug-ins to decrypt and encrypt email (Pretty Good Privacy)
• Graphics software use plug-ins to support file formats and process images (Adobe Photoshop)
• Media players use plug-ins to support file formats and apply filters (foobar2000, GStreamer, Quintessential, VST, Winamp, XMMS)
• Packet sniffers use plug-ins to decode packet formats (OmniPeek)
• Remote sensing applications use plug-ins to process data from different sensor types (Opticks)
• Software development environments use plug-ins to support programming languages (Eclipse, jEdit, MonoDevelop)
• Web browsers use plug-ins to play video and presentation formats (Flash, QuickTime, Microsoft Silverlight, 3DMLW)
• Some digital mixing consoles allow plug-ins to extend features such as reverberation effects, equalization and compression.