What is C2H5-O-CH=CH2?
The particular reaction is of acetylene ($\ce{C2H2}$) and ethanol ($\ce{C2H5OH}$) to yield ethyl vinyl ether (IUPAC name ethoxyethene). It's one example of Reppe chemistry, a fairly diverse set of reactions, often operating on alkenes and alkynes (though certainly not exclusively). The specific reaction in the question is a vinylization reaction, though it was Reppe's carbonylation reactions which were probably of greater practical (read: economic) import historically, as they were famously used in the Monsanto process and in production of various acrylates and other acrylic acid derivatives.

The vinylization reactions could still be synthetically useful, as they provide an extremely simple alternative route to vinyl ethers without having to proceed via elimination, substitution, coupling, olefination, or substrate-specific oxidation reactions.

I'm not aware of any specific uses for ethyl vinyl ether, however it could certainly be used as a building block in any number of organic syntheses.