Without a doubt in my opinion, the invention of the World Wide Web (www) impacted IT the most. My understanding is that the Internet existed long before the advent of the web but it wasn’t until its existence when anyone could start going online, let alone use a computer for more than just typing documents and using a painting program in the 1980s.
As IT stands for Information Technology, the web has a lot to owe for us getting our information from websites made only possible from the technology that allows us to access it (computers). The fact that websites being linked together allowing for individuals and organizations to put out information as diverse as blogs, review sites, social media and yes, online classes like the one we’re participating in, is a testament to how powerful and impacting this invention was, is and always will be.
The essence of IT after all is communicating ideas through technological means (or telecommunicating). It’s very hard for me to see how this would be remotely possible without the web for us “normal” users; I honestly have no idea how raw Internet alone (without web) can easily replicate this; it just can’t.