resence Ser- vice (IMPS). IMPS has four features: Instant messaging-Instant messaging is a type of electronic communica- tion service that involves instant communication between two or more peo- ple over a network such as the Internet. Presence-OMA's definition of presence includes client device availability (my phone is on/off or on a call), user status (available, unavailable, in a meeting), location, client device capabilities (voice, text, GPRS, multi- media), and searchable personal status, such as mood and hobbies. Groups or chat-IMPS enables both wireless operators and end users to create and manage groups and group discussions. Chapter 16 Emerging Wireless Applications Shared content-IMPS allows users and operators to set up their own stor- age areas where they can post pictures, music, and other multimedia con- tent. That content can then be shared with other individuals or groups of users in either an IM or chat session. The IMPS standard was originally proposed by Nokia (www.nokia.com), Ericsson (www.ericsson.com), and Motorola (www.motorola.com). The IMPS specification, which is managed by the industry consortium OMA, defines how the system should interface with existing wireless network infrastructures. IMPS also provides an open interface to existing IM communities such as AOL (www.aol.com), Yahoo (www.yahoo.com), and MSN (www.msn.com). In order to engage in IM on a mobile with IMPS, the user needs a phone with an IM client as well as IMPS to connect to. The OMA IMPS Enabler release is designed for exchanging instant messages and presence information not only between mobile devices but also between mobile and fixed devices. IMPS 1.2 was approved and released in January 2005. IMPS 1.3 Enabler, a candidate for the next upgrade, is a significant enhance- ment of IMPS 1.2 Enabler, although it is not designed to be backward compatible with previous IMPS versions. There are many obstacles to bringing mobile presence and IM services to mar- ket, from technical and business issues to user awareness. The big