Dopplr recently launched a new version called “Copenhagen” and amongst the new features there is this possibility to insert new trip to Dopplr directly via Twitter (and also by SMS or email). All you need to do is reply to Dopplr with the trip information (eg. “A trip to Helsinki on May 19 to May 23”). Mixin is also using Twitter to feed your social agenda. Problem is that every service requires to fit a given format (for Twitter: “mention a placename and two dates, including the month both times”) that 1) you have to remember, 2) is most likely not compatible with other service. Next step would be to feed those services with natural language…

Also it is interesting to see that Twitter is becoming the “de facto” status aggregator as it is used to feed other services (it is a bit surprising as well given the lack of reliability of this tool that keeps on crashing).