__declspec( dllexport/dllimport )

Could you please explain to me the purpose of dllexport/dllimport. I've read that the dllexport statement makes the function/variable available to anyone using that .dll. (which seems to be untrue about variables.)
I know very little about .dll's so please give the explanation in simple terms.
Thank you.

http://msdn.microsoft.com/en-us/library/9h658af8.aspx

dllexport is used in the DLL to decide what to expose to clients, dllimport is used in the client application to tell the compiler that some variable or function comes from a DLL.

To use a DLL you link your application against its import library. Alternatively you can manually load the DLL and find the symbols you need but that's a lot of unnecessary and ugly work.