Walking at a path, you watch vibrates and shows a
message "there is a nice water feature to your right". You
peer closely to your right, and see indeed it is very nice.
You press the up button to vote up the message.
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The concept is simple. While hooking up to a
twitter/annotation/etc...
database.
If you are walking around and you hit a certain GPS
coordinate, you can receive short messages related to
the area, placed by a person who was at the location
before.
This can be received on your smartphone. But I think this
is
more handy for your smartwatch (e.g. pebble, apple or
android smartwatch).
If you like the message, you can swipe or press up. If its
useless, then swipe or press down.
So those who place good useful geo annotation to a
location will be heard more often.
Twitter could be a good source of messages, but you
want a dedicated message store... otherwise old
messages may be harder to trigger.
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You could also join groups of people of similar interest,
so that their aggregate of voting patterns will more
closely match yours.
Think of this as social bookmarking, but location based.