I don't know, thousands of small companies run forums online for customer interaction and customer support purposes. If this law is written in a bad way, BAM, suddenly no Russians will ever be allowed to create accounts on those forums, and no small company is going to go rent a server in Russia and dedicate engineer time to tying the two together so that Russians can register and login to a forum in Russia, but yet still see a single view of all the public posts and threads that exist on the "internal Russian" site and the external general site.
Literally, this means that forum owners need to put a little line on their registration page saying "sorry, no Russians allowed". And despite that, there's the possibility that the companies would suddenly be liable and in violation of Russian law for existing/prior users, and any users who sign up anyways, and any Russian users who sign up while obscuring their identity or origin (and what, are you a small company really going to put in filters on source IP addresses and hope that covers you, etc etc etc).
I understand the intent of the law, but I bet they write it loosely enough that they shoot tends of thousands of companies the world over in the foot.