well you can use it as a replacement for email.
you can use it to work together on a document with a collegue.
there are tons of practical uses.
you can use it to share multiple photos with friends...
essentially, its a good alternative to email. provided your friends have access to a wave account.
it makes it very easy to share photos.
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but the real fun is when you have 3-4 people collaborating together.
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i saw the raindrop demo video. it looked more like a dashboard which you can use to manage emails, twitter accounts, facebook updates and other stuff.
its not for collaboration. its the intelligent inbox.
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[video=vimeo;7197666]http-~~-//vimeo.com/7197666