Hello,

this question, however, is kind of harder to answer. It's because it really depends on your hardware and hosting/server environment at all and the things that users do on the site.

It means that the info about the logged users is stored in a session either located in the RAM memory or in the database. If you store it in database, it is more reliable, but significantly slower I guess. Therefore, I would recommend you to store it the standard way in memory and make sure there is enough RAM on the server.

In conclusion, if we are speaking about hundreds of thousands of users, it should be OK with Kentico CMS, but of course you need to have appropriate hardware for it.

Best regards
Ondrej Vasil