We need to do an email product roundup. So many smart people are trying to improve email but the largest success I can think of is Mailbox.
Toastio is another creative approach, limiting emails to 350 characters (not yet launched).
Mailbox seems to be the clear winner for client (through Sparrow had its run) - Baydin/Rapportive/Yesware/Streak/Tout have all established themselves as valuable plug-ins. http://www.baydin.com/
I am really curious to see Toastio. Constraint enforced by a platform, where everyone else must follow it, seems to be key. It cuts through the game theory that prevents open platforms from noising themselves to death
Product Hunt
Hear and Now
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