I'm a total noob when it comes to servers, so I just wanted to get a rough idea of how much some of the most visited sites in the world cost to host. What's your rough estimate for Stack Overflow's monthly server fees?
Every CoLo will charge you a different amount depending on location of the CoLo, proximity to the back bones, and how full the CoLo is.
Here is SoCal rates are pretty easy to figure out.
A full 42U rack will cost you $650-850 a month.
Each 110v power circuit will cost you ~$250 a month. Each 220v power circuit will cost you ~$800 a month (and not everyone offers 220, but almost no one actually needs it, except my company). Some places charge you per kVa on the power, but if you aren't planning on adding and removing hardware a flat rate is easier to deal with.
Bandwidth is where the numbers really start to fluctuate. The more you buy the cheaper it gets by the meg.
When I was looking for a CoLo some prices that I was quoted were (this is for a 20Mbps circuit): $940 $2820 $1520 $2000 $1100 $300
Different companies have different qualities of bandwidth available, as well as different SLAs.
Now you said most visited, sorry but the trilogy has a lot of traffic, but no where near what some of the biggest are at.
MySpace for example (when I worked there 2-3 years ago) had 3 data centers in the LA area. They used more power than Chernobyl put out when it blew up.
FaceBook is in the same basic area, but they are now building the first data center which they will own. Sites setup on this scale cost millions per month just to keep the servers on and connected to the internet, not to talk about the hardware costs.
Well all of StackOverflow's servers are Co-located, so they own all the hardware and it's Co-Located in a Datacenter. For some ideas on the initial outlay take a look at this blog post. Obviously the current amount of hardware is now greater than that.
So as for co-location costs, the servers are co-located with Peak internet, and I assume by the fact they get free advertising on all the sites are offering some discount to the guys for hosting costs. Co-lo costs will take into account Rack rental, Bandwidth and Power, it might be possible to guess what sort of bandwidth the sites are pulling from the public information available, and I guess you could work out the power needed by looking at the specifications of the servers, but its going to be a lot of guessing because we don't know what the DC is charging.
They run a full rack off of one 1Gbit ethernet line going to the host. Without discounts such hosting typically costs $300/mo to $3,000/mo depending on overall bandwidth, power requirements, peering redundancy, and miscellaneous host provider differences.
You could certainly call up Peak and have them give you an estimate for a similarly sized system.