I posted a question in the house forum. I also read the real estate forum a lot, and have noticed that I do not see a lot of real estate forum people posting in the house forum. My question had to do with a remodel keeping resale in mind. So I went to the real estate forum and asked people there to look at my post in house (along with giving a short summary) and give me opinions from a real estate professional opinion.
I've seen people post in house asking about increasing showings, they get referred to real estate, and no one comes and deletes their post in house. Same with the state forums. For example, you can get a "I'm have a job in DC, should I choose NoVA or Maryland?" question in both Virginia and Maryland.
With the shear number of forums that city-data has grown into over the past year, it is reasonable to assume that not everyone reads every forum. And sometimes, the poster might want the opinions from two different groups of people (i.e. DIY-ers in house and real estate professional, or Virginia lovers and Maryland lovers). I can' understand you don't want someone to cross-post something to every forum. But it seems like tailored cross-posting when the groups are unique and might have unique opinions should be allowed.
Maybe I'm just too old-school Internet. Back in the Usenet days, cross-posting was often encouraged.