I know that you can go on the Microsoft site and post on the newsgroups
there but is it the same as doing it on Google Groups?

Yes but different servers. A newsreader will give you more controls
about what message content you will see, enabling you to block some
posters or types of messages.

Google bought Dejanews which had a lot of old posts to usenet archived.
They have updated the way that it is now handled, realising that most
of the old stuff is an invaluable resource.

However they have no real intention to moderate it, so a great deal of
bad stuff gets out there too. Microsoft can control what appears on
their sites.