I have been working with nonprofit organizations for years. I have what may be the best spam filter on the planet and it costs me very little to run it. I'm not rich - but I can afford to give this service away.
Nonprofit orgs waste a lot of time and money every year deleting spam and viruses.Most solutions are expensive and just plain don't work. The way I see it - I'd rather nonprofit employees spend their time doing good work rather than spending hours every week deleting unwanted email. And - I have a system that solves the problem.
The way it works is that your email comes from the internet into my servers. I process it - and send the good email onto your existing email server. So - nothing on your end has to change. Once this is set up - everything is the same - except the spam and viruses are gone.
The setup is simple. Once you decide to do it all I do is make an entry in a table on my servers telling the system what domains get forwarded to what servers. Then - you change your MX record from pointing to your email server to pointing to my server network. The email comes to me - I clean it - and then you get it. It really is that easy.
What does it cost you? Nothing! All I ask is a thank you on your thank you page and a link to my service. That's all I want - and that you spend your time accomplishing great things. To me - this is a way that I can donate what is equivalent of millions of dollars in your savings at a cost to me of almost nothing. It's an extremely efficient form of giving to me.
What is a "progressive" nonprofit? As the name progressive implies - progress. The word progressive to me means that the stated purpose of your organization is something that advances the good of humanity in the real world. And although this is a fuzzy line some example of what I consider progressive would be organizations that feed hungry children, provide medical assistance, legal aid, human rights, peace, freedom, and things like that.
As to what is not "progressive" in relation to this free offer are most religions in general, front organization for cults, organizations that are harmful to the good of society, organizations that are mostly self serving or hobby related. Not that all these things are bad - just not in the class that I'm offering free service to.