Basically here's the way it works:
Most popular sites run into the same issue -- more visitors than the site can handle. I know of one popular Theme site that is essentially down most of the time for everyone because it can't handle so many connections. (in fact, I just checked and it's down right now "failed, too many connections").
At WinCustomize, we could have that same problem. But we don't. Why? Because when we start to near the maximum connection load the site simply picks and chooses who it's going to let in.
Rather than no one being able to connect, it gives priority to 1) WinCustomize subscribers then 2) SD customers and then 3) People who have at least created accounts and then 4) Everyone else.
I'd much prefer a system where those who contribute can ALWAYS 24/7, 365 days per year get to the site and have a reasonable surfing experience than a system where it's down a significant portion of the time due to being overwhelmed with traffic.
According to Alexa, WinCustomize is the world's most popular customization site. Someone has to pay for that bandwidth, servers, etc.
And hey, if the software is so terrible then problem solved, no need to download skins and themes and icons for "terrible software".