Suspicious ads for freelance writing gigs

There are just some ads for freelance writing gigs that set off warning bells in my head. There's not always a definable quality that alerts my scam senses, but certain things — not enough information, get-rich-quick promises, the "perfect for stay-at-home moms" statement, and gigs that involve you making money by recruiting others — are super-sized red flags.

Here is an ad I saw on my local Craigslist that made me highly suspicious:

Writers Wanted

Reply to: see below
Date: 2009-01-24, 9:39AM MST

Interested in writing a short article (1-2 paragraphs with photo), one per month for a family safe classified ad website? There is a large range of topics to choose from, anything from recipes and golf tips to movie reviews and arts & crafts. You can make hundreds of dollars per month by helping this website grow in valuable content. For each additional person that you can find that would be willing to contribute once a month article or review you will earn $12/person/month with no out of pocket cost ever. Call (XXX) XXX-XXXX between the hours of 7am to 7pm MST.

* it's ok to contact this poster with services or other commercial interests
* Compensation: Average income $50 to $250/month

Here's a rundown of why this ad makes me suspicious:

* "You can make hundreds of dollars per month"
* Make money by recruiting others
* "No out of pocket cost ever" — why is this necessary to state unless it's some kind of scheme?
* Not enough details about the gig or the website
* Phone number is NOT local
* No name, email address, or URL — meaning you can't research the company

If I didn't hate telephones so darn much, I would call the number myself and investigate. Any volunteers? If so email me and I'll send you the number.

I would love to compile a list of red flags or warning signs in freelance writing ads, to post for all of our reference. What are some reasons why you will pass over an ad without applying?