Re: Problem with running your own mail server now is the big 3 do not trust your email by default
> I have a server set up in a dedicated hosting centre as well, as we send
> out newsletters to around 1500 people a week, and again largely no problems,
> nor indeed with the various welcome messages when people sign up to that site.
It's quite likely the address space or IP address you use is set as trusted. You can very roughly check how reliable the big guys trust your mail server by using SenderBase at http://www.senderbase.org/ as a good (But not definitive) guide.
> If what you're suggesting is true, how would anyone ever be
> able to launch a new service that requires verification of users'
> email addresses?
Or for that matter, any plain mail server? Simple answer is you can't, at least not with the emails shooting straight into the spam folder by default. It really is a bad problem. And for some bizarre reason, using certain mail server software exacerbates the problem for no good reason. For example if Outlook/Hotmail sees email from an IP address they haven't sent mail from before and sent through the Zimbra Groupware server, it won't even make it into the spam folder!!