The platform you're using- a website on the Internet- was funded for, and developed by, NSF (many other orgs contributed). They played a critical role in the 1980s when the net was in a period of tremendous growth. They helped enable the transition of the internet from a military/academic research project into a huge driver of the economy. That's just one example but they played critical role in developing many other science and technology.

I find in conversations like these, if I don't know something fundamental like the NSF's role in American science, it's pretty easy to do a short bit of research before commenting. It's not bad to ask questions, but I figure if the question has a basic factual answer in wikipedia, it's best to start there.