How Did SEM Morph Into Paid Search?

About two or three years ago, I noticed more and more people saying SEM when they meant, to me, paid search. I�d hear people say things like �We do SEO and SEM,� as if SEO wasn�t a part of SEM. I found that grating. I�d usually chalk it up to people either making an innocent mistake or perhaps still being new to the space.
Recently, it�s only gotten worse. I also hear it from people from large companies that I�d say should know better. But this is where I have that �Am I swimming against the tide?� feeling. Maybe it�s me that just hasn�t adjusted. I�ll come back to that, but first, how did this change come about?
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