It sure beats instant coffee. A major change to Google's results page has created an intense interest in interfaces that provide immediate feedback. Google Instant, which updates search results as you type, inspired YouTube Instant, which many developers have emulated using a number of different APIs.
When Google launched its auto-updating results page, developer Feross Aboukhadijeh decided video searching needed the same instantaneous flair. Using the YouTube API Aboukhadijeh created YouTube Instant and ended up getting himself a job offer from the search giant.
Perhaps encouraged by Aboukhadijeh's success, other developers have gone on to create instant mashups (we currently list four) based on other APIs. Google Maps Instant has received the most attention. The site geocodes as you type to show the location of your current search. StoreSlider uses eBay's API to show auction results as you type. Another, Instant Job Search, is true to its name. It takes multiple job listing APIs and combines the results, all instantly--or, as quickly as possible.
Instantly Web takes the idea of instant search results to the next step. Using Google's Ajax Search API, the site automatically loads the first result in a frame below the search box. In other words, there are no search results. You get just the single page that Google has determined to be the best answer to your query, updated as you change keywords.
The trend is certainly made possible by APIs. Even Google's own implementation uses a home-grown call--a private API--to grab the latest data. But it takes more than simple Ajax to make an instant app as responsive as Google's. For starters, when you send out a request based on the user's typing is an art. And your server needs to be up to snuff, as must be that of the API provider. Mashing up more than one API, as some have done, makes the job even harder, as there's more data to retrieve. The result may not be so instant.
The "instant" trend, as many developers have likely noted, is more about a snazzy interface than it is a technical hurdle. Yet, it has given rise to this new type of mashup and APIs are being used in a different way because of the trend. But we'll still wait three minutes for the coffee to brew.