Treat each network separately
It's not unusual to have personalities across several social networks and a burning desire to give the same information simultaneously to Facebook, Twitter, and LinkedIn. Don't make this an automatic thing.
"They're different networks, and have different syntax and etiquette, so syncing all of your tweets to Facebook is usually not a good idea," said Lauren Dugan, editor of AllTwitter.com.
It's OK to tell the networks the same thing, just don't make it a one-stop entry. It may take more time, but it's less irritating to see messages tailored for the network.