6 hot apps that Silicon Valley insiders are buzzing about

· To be part of the in-crowd in Silicon Valley, you have to know about and use the latest hot new apps.
· Years ago, that was Gmail; this week it's Hey, a new email service.
· Below is a list of six of the hottest apps in the Valley.
· Unfortunately, most of them are invitation-only, so there's good chance you won't be...