I did the same thing you just did and if you watch how he explains it again it works out the same way. I think the saying /C for not having class was more intuitive for me as well, but in both ways you reach the same conclusion that the other option was that there is a possibility of class when there is over 3 inches. In your case just 3+ and C. Again, same answer with different notation for C. Hope that helps!

From what I have read, not only will they google your name and look, but they will do searches through various social media sites to find things. Mostly the main spots like X, Instagram, and Facebook, but if they find you on other sites its very possible they could look through it.

If you have private accounts with nothing questionable in your bio or profile picture you really should be okay. If your reddit account is not connected to your name or not otherwise easily linked to you I think its incredibly unlikely they would ever find it. The online searches for applications is mainly for people who post edgy stuff or have a damaging digital footprint which could reflect poorly on the school looking to admit you.

Don't quote me on this but I remember reading something a few years ago about a group of guys that got admitted to Harvard but were then denied admission after the school found their Facebook group where they were being openly offensive online.

With that being said, I still do not have any public accounts excluding my LinkedIn profile. Even if some may call this unnecessary, it is great peace of mind, and it could be a useful strategy just to give you one less thing to worry about for admissions. There is nothing bad admissions officers can find out about you online if there is literally nothing for them to find.

I hope this was helpful lol. Best of luck in applying!