FaceBook is hands down our biggest competitor. Thankfully our members are looking for anonymity and many aren't willing to "share" on FaceBook. We've harnessed that power thus far but it's going to be difficult moving forward as long as we're not ahead of FaceBook technologically and intuitively!!!!
I'm not positive I'd wait. IPB will release the public beta in a few weeks? How long will it take for a truly stable release? 6-9 months - at a minimum ? Guess it really depends on your budget and launch timeline.
I meant to say.....You could "technically" run a mail server on any computer that has an IP. I don't suggest you do this since your IP will be blocked in no time.....regardless if you're spamming or sending legit emails.
Headaches ?! It should take you 5 minutes to set up Mandrill. We send 1+ million emails per month and have tried many solutions. We moved from SenGrid a few months ago and we're really really satisfied with Mandrill. The pricing and feature set is better than anything else out there.