If it is a condo, it should be described consistently as a condo, and the same for a co-op. They are very different animals. If you are referring to here, on Trulia, I am in complete agreement that there is a lot of erroneous information in the listings. That is because Trulia "scrapes" other webites, and does not check the content.
If you are serious about buying, the best thing would be to work with a skilled, experienced agent. We use the agent database (and as you can see in my signature, can give you a window into that database), streamline your search, negotiate on your behalf, and take you through all the steps of the buying process.
Sellers all have agents and so should you to level the playing field.
Halstead Property, LLC
http://jenetlevy.halstead.com for all NYC listings