The term Cyber Monday is fairly recent. Shop.org is reputed to have created it in 2004. The idea was that people would be going back to work after Thanksgiving and using their employer's fast internet connection to do their Christmas shopping instead of doing it at home through a slow dial-up line.
The whole idea is pretty out of date. Who uses dial-up anymore? Most people have cable or DSL. Heck, my cell phone has 4G which is fast enough for streaming video and I can use it for an Internet connection if I really need to.
By now the thing has taken on a life of its own with Cyber Monday specials but it's all pretty silly. Christmas is still a month away (ok, 29 days) and nearly everyplace promises delivery in less than a week.
So, don't feel that you have to buy something today just because it is Cyber Monday.