There are categories of “jobless” that the advertiser is probably illegally discriminating against, under the local Fair Housing guidelines:
Retiree.
Person who can’t work because of a physical or mental disability.
Person receiving Social Security after the death of a spouse.
Person who lives on his or her alimony or other support payments.
Person who hit the lottery/has a trust fund/won a lawsuit and is living off the income.
I see that the OP is in Massachusetts, but I can tell you that here in Ohio the Fair Housing people would be all over that ad like hair on a gorilla. They earn their salaries by suing people. I realize that the example is a person looking for a roommate, not a tenant, but you can just try to convince Fair Housing of that.
When I was working at our local newspaper, we had an ad placed by a man who was looking for a roommate. There was no reference to sex, race, religion, or any other warning sign in the ad; yet an interested person who called was told he “wasn’t looking for black chicks.” The woman called Fair Housing, who sent out a young black woman as a tester. When she was rejected, they filed suit. The newspaper was not named in the suit because the ad was 'clean," but believe me, they would not have hesitated to include us.
The rule is, you can ask the applicant to demonstrate that he or she can afford the rent, but you cannot ask how he or she comes about the money (as long as it’s legal). If you’re asking $500 a month, and the person can give you $500 a month in legal money, his/her being a “student” or a “professional” or a retiree or a welfare mom is none of your business, in the spirit of the law.
That’s why so many people use word-of-mouth and college newspapers to find roommates, because they are not policed as often as print publications. Craigslist is beginning to be mined for Fair Housing lawsuits; they won one recently on the premise that “Craigslist is not a publisher,” but the individual advertisers still are liable.
Cite: http://www.theinquirer.net/gb/inquirer/news/2008/03/15/appeals-court-affirms-dismissal
Our newspaper would not accept a housing ad that said “student” or “professional,” either from a landlord or a prospective roommate. Too much trouble and nobody wants to go to those Fair Housing “training sessions,” at which the director rants at you for four hours while charging you $50,000. (Then you’re trained.)