Yes they are!
The FHA specifically applies to housing ads!
>The legality of a given ad depends on many factors not always present in the ad itself -- such as whether the landlord lives in one of the units. All of the above selection criteria are perfectly OK to filter by if a landlord occupies a unit in a building with less than 4 units.
No, discriminatory ads are illegal (other than sex in a roommate situation) even though discrimination in selection is legal in some cases.
>It's also legal to advertise for other criteria like race in these cases -- though it's not socially acceptable
No, it's not legal.
If you post a housing ad on Craigslist, they tell you all this.