Lurkers are important to a commercial site... even if they don't sign up it is still traffic so segregating them is just not going to happen IMO...
I am of the short and sweet sect,,,I don't want to wade in a place that the primary purpose is duscusion... I can see it in a graphics or art forum,,,just not a discussion forum... I was into computer tech forums once and I could see sigs as they showed off there Computer rigs,,,it was almost like part of the discussion and when trying to solve someones prob it was good to have their setup in their sig to go by...
I haven't got a server busy in a while but I noticed throttling bandwidth to accommodate the times that are busy so I expect more load would cause probs... there are all kinds of sites and all kinds of situations,,, if this site was more lucrative I would imagine it would accommodate the peoples choice more but,,,I think it will have to grow into more bandwidth for graphics rather than risk meltdown and rush into it... My 2