Google Talk is not just an instant messenger, it's a communication platform.
One of its use was Gmail Chat, a great way to chat with your contacts inside your browser. You don't need an application and the message is instantly received if your contact is online. "See when your friends are online and decide for yourself how you want to get in touch with them. Email and instant messaging don't have to be so different. And why should you always have to remember whether something important was said over email or IM? We've made it easy for you to save chats, so you can search for them, print them, even reply to one over email."
Google Desktop also uses Google Talk and it integrates the application into the sidebar. Google Talk is the basis for Google Desktop Sidebar Communication API. "Google Talk serves as the communication medium for Sidebar gadgets. If a user is logged into Google Talk, a gadget can get a list of which of the user's Google Talk friends are currently online. Once it has the list of online friends, a gadget can send and receive data from the same gadget running on an online friend's machine." One simple example is a game, a more complex one could be synchronized file sharing.
Even though it's not used explicitly, Google Spreadsheets has a feature that allows you to chat with the persons you're sharing your file. "The chat window is a convenient way for you to see who else is viewing and editing the spreadsheet at the same time as you. You can chat with each other about the changes you're making, in real time."
And Google doesn't want to stop here. "Our users love the chat integration within Gmail, and we're planning to make it easier to chat with your buddies through other Google services," says Lewis Lin from Google.
When they talk about LibJingle, a library that implements some extensions to XMPP and it's used extensively in GTalk, an interesting phrase is mentioned: "In addition to enabling interoperability with Google Talk, there are several general purpose components in the library such as the P2P stack which can be used to build a variety of communication and collaboration applications. We are eager to see the many innovative applications the community will build with this technology."
Some of these innovative applications will be used by Google and integrated into their services. A chat for Writely or Google Calendar, an easier way to share files online, real-time collaboration in Google Search - all of these using Google Talk network? They're not out of reach.
What's so great about Google Talk's future
Google Talk tips
Android Police Podcast Ep.211 - A Very Ample Spacebar
16 minutes ago