Google Talk has not been updated for 5 months (support for Windows Vista appeared in the latest update), which means that there should be some important features in the next release.
A plausible hypothesis can be considered the possibility in the new version to make calls to SIP, or regular phone numbers. Google has inserted a screenshot of a future version of Google Talk into its Google Apps presentation .
In this screenshot, you can see the buttons “Show dialpad” (Show dialpad), “Call details” (Call details), as well as the search panel with the caption “Enter a name or phone number” (Enter a name or phone number). ')
Interestingly, it will be paid, or is it a free analogue of Skype Out? Although, in any case, I'm really looking forward to the new version of Google Talk.