The EWS protocol is one of the most complex protocols to support, have severe license restrictions and really, doesn't have a lot of *casual* users. To support business customers, you'd often have to sign contracts to provide support for those users . Most startups don't have the resources to do any of those things, so they'll go after for the majority of the markets and that's IMAP, which on its own is very difficult to support but you get paychecks quicker than other protocols.As far as I can tell there's outlook (horribly overpriced) and Apple Mail. What's the holdup? There are some outstanding mail applications out there but they only support pop or imap and not EWS. Is this a microsoft problem?