Starting tomorrow, ProPublica will begin publishing advertising on its web site, and likely soon we’ll include it as well in our daily email, on our mobile site and in our iPad app.

We’re doing this for the usual reason: to help raise revenue that can fuel our operations, promoting what people in the non-profit world call “sustainability.”

ProPublica, as you probably know, has been funded almost entirely by philanthropy. Much of that has come from our founding donors, the Sandler Foundation, and from other foundations. More recently, some has come from people able to make large gifts. And important support has also come from readers who have contributed what they can. (You can click here to become one of them.)

We’re delighted to report that we had more than 1300 donors in 2010, up from just over 100 in 2009. Funding from sources other than the Sandler Foundation came to more than $3.8 million, or more than 38 percent of all the money we raised last year. In 2011, we aim to increase that to $5 million, 50% of the total. Advertising will help us get there.

We’ve become part of an ad network called the Public Media Interactive Network, and have arranged to be represented for web ad sales by National Public Media, an offshoot of NPR and PBS. But if you’re interested in advertising directly, especially on our daily email newsletter that currently reaches more than 40,000 people—triple the number of a year ago—please let me know.

In connection with the decision to take advertising, we’ve also crafted an Advertising Acceptability Policy, which is principally intended to avoid reader confusion and bad taste. It can be found here.