Disposable apps is a popular term for applications built rapidly by "power users" who need to address a specific problem only relevant to a few people for some period of time. Example: How do I find an apartment in Austin close to a running trail and an Internet cafe?
Yahoo Pipes is a tool enabling disposable Web apps. Microsoft is competing via Popfly, Google has Mashup Editor.
Web mega-brands are beginning to figure out ways to secure long term consumer loyalty by enabling power users to extend their networks of services.
While Yahoo Pipes is an awesome data flow oriented app design tool, it leaves out the domain of communications apps. For example, it is not possible to build a pipe, which 1) monitors an RSS feed for new sports cars and 2) when a new car is posted, and 3) when Alice and Bob are both online during off-hours, then 4) connect them and 5) pop-up the new car web page so they can discuss it. With slightly different parameters, the same application can be useful to a person looking for a house with given criteria and is interested to discuss with their broker each new offer on the market that matches the criteria.
These examples are in the domain of converged applications - mix of web and communications features. To make them possible, there needs to be a foundation of basic communications services pluggable into mashup editors like Yahoo Pipes.
British Telecom made a brave step in the right direction with its new Web21C SDK program. Although BT SDK cannot be readily plugged into web mashups, it is just a small step away.
Another practical example is a mashup between Google Calendar and a hypothetical Conferencing Service similar to the one offered by BT. Lets call this mashup - GCal Conference Service. Its purpose is to make conference calling a better experience - it won't require people to remember the exact time of a conference; they won't need to have a conference bridge number handy either; they may even be stuck in traffic on their way to the office as the call begins.
GCal Conference would work as follows: 1) It will monitor the RSS feed of a user's calendar and watch for events tagged as Audio Conference. 2) 5 minutes before the event starts the service will create the conference room and begin joining participants to the call. The list of participants is found in the GCal event. Address book will be used to lookup each participant's phone number.
Undoubtfully there are many other ideas for disposable converged apps. We are barely scratching the service of what will surely follow. There will be telco players who will hop on the rising tide and ride it. There will be others who will continue contemplating their next big move and find themselves left behind in the 20th century.