NaBloPoMo stands for "National Blog Posting Month." The goal of NaBloPoMo is for participants to write a post a day for an entire month.
Although November is the official month for NaBloPoMo (with prizes and everything!) people are invited to take up the challenge of writing a post a day during any month. To help inspire bloggers, NaBloPoMo assigns a theme for each month, and also offers daily writing prompts, but these are optional. Bloggers are not required to write on a specific month's theme or a specific day's writing prompt. Any post about anything at all counts.
NaBloPoMo was created by Eden Kennedy who wrote:
In 2006 I started NaBloPoMo as kind of a joke because I'd failed at NaNoWriMo the previous year. I decided that if I couldn't write a novel in thirty days, at the very least I could post on my blog every day for a month. I thought maybe thirty or forty people would do it with me. We ended up with around 2,000 bloggers, I think. In 2007 we moved to a real web site and got almost 6,000 people, and by January of 2010 we had more than 16,000 members. WHERE DID ALL YOU PEOPLE COME FROM?!Eden did a fantastic job running NaBloPoMo, but it was a lot of work and she'd never really intended to run anything! In 2010 she approached other organizations about taking over NaBloPoMo. NaNoWriMo never got back to her (it would have been perfect if they'd agreed since this was kinda their fault!) BlogHer did respond and NaBloPoMo is now hosted there.
I have mixed feelings about the "new" NaBloPoMo. I'm a huge fan of the original! It was small, quirky, and non-commercial. But I understand the reasons for the change and I appreciate BlogHer and Eden's efforts to keep the event going rather than having it disappear into the ether.
Best of luck to anyone, at any time, who decides to take up the challenge.
Edit: I've written an Unofficial Guide to NaBloPoMo to help bloggers find their way around the new site.