We all know about “too big to fail” and its repercussions for the economy. But what about “too important to fade away?” To me, that’s the story of Idealist, the pioneering online community for the social sector- and its current fight to survive.

A week ago, Idealist founder Ami Dar sent a warning note to friends and supporters. After 15 years, the site and its incredible range of listings and services, was in trouble. Here’s what Ami wrote – and Tweeted:

Very briefly, here’s what happened. Over the past ten years, most of our funding has come from the small fees we charge organizations for posting their jobs on Idealist. By September 2008, after years of steady growth, these little drops were covering 70% of our budget.

Then, in October of that year, the financial crisis exploded, many organizations understandably froze their hiring, and from one week to the next our earned income was cut almost in half, leaving us with a hole of more than $100,000 each month.

That was 16 months ago, and since then we’ve survived on faith and fumes, by cutting expenses, and by getting a few large gifts from new and old friends. But now we are about to hit a wall, and that’s why we decided to ask.

To may way of thinking, Ami and Idealist saw the good cause in the early Web and pursued a path of service to nonprofits and causes. Its decade and a half of service should not be ignored with a pat on the head and a retirement certificate; indeed, the rest of the ‘CauseWired’ web stands – in large part – on Idealist’s shoulders.

Sure, the business model may need tweaking in a classified world dominated by Craigslist and a device-centric landscape of iPhones and Droids. But let’s chip in to give the Idealist crew that time to explore and grow and survive. I’m fond of telling corporate leaders than the social web – and by that, I mean the philanthropy sector – is actually ahead of consumer brands in using social media and building and supporting communities. Let’s prove that right by helping Idealist.org right now.