First of all, you can have a thousand users online at the same time that are not basically doing anything and not see a slow down but you can have a 100 that are doing things that causes a load on the server; that requires a lot of database queries etc, and have a site crawling on its knees.  I have noticed that UNA is slower at just loading the main page than Dolphin.  You want a page to load in just a couple of seconds for a good user experience.

What a lot of people don't understand is that UNA is not all brand new code; for example, the studio was written ten years ago.  Plus, some of the coders that use to be with Boonex are gone now.  Perhaps we should write some scripts to simulate a site with real users doing real things; like uploading videos, engaging in chat, streaming videos etc and get some idea if UNA is suitable for a real social networking platform.  Who knows if the sql queries have been optimised?  I don't.