How to tell if REO?

[T Brown]

Hello all;
I am new to this board and to REI. I am interested in being a buy and hold investor. I have a couple of questions I hope the experts here can help me with:

1. When I am looking at the properties on the MLS (realtor dot com), how can I tell what is REO? Is it mostly by price? Or do I get the address and look it up on the county assessment site to see who owns it?

2. I have seen a couple of seasoned investors here mention that they don't tell people what area they invest in. Why don't they want to tell people that? How will they get good deals from wholesalers and agents if no one knows what they're looking for?

Thanks again for the help!
Trina