How to interpret traceroute information?
The 12 lines are the nodes the packet had to go through to get to wikimedia's server. You need to go through 12 nodes because your computer isn't connected directly into wikimedia's server. It is connected to a node at xs4all.net (an ISP, naturally), which is connected to another xs4net node, which is connected to wvfiber.net, which is connected to as30217.net, which is connected to wikimedia.org, so that's the best path the routers could find to get the packet to the destination. If your computer was plugged directly into the target computer there would be only one hop; try tracerouting to another computer on your local network:
> [mrozekma@etudes-2 ~] % traceroute etudes-1
traceroute to etudes-1 (192.168.0.10), 30 hops max, 40 byte packets
1 etudes-1 (192.168.0.10) 0.196 ms 0.190 ms 0.152 ms
The timing information on the right side of each hop is the round-trip time for the packet. By default three packets are sent per hop, so it shows three timings; if you give traceroute the -q option you can control how many packets are sent:
> [mrozekma@etudes-2 ~] % traceroute -q 1 etudes-1
traceroute to etudes-1 (192.168.0.10), 30 hops max, 40 byte packets
1 etudes-1 (192.168.0.10) 0.177 ms
The hosts shown by traceroute are not servers, they're routers. Traceroute shows the hops on the IP route from the computer of the person who took this snapshot to the wikipedia server. The description of HTTP that you quote looks at a much higher level where all this routing is transparent.
I think the best way of explaining this is through a metaphor. HTTP (for example) requires a bidirectional communication channel between the client and the server; this channel is provided by TCP. TCP is built in turn on top of IP. The goal of IP is to transmit packets from one IP address to another. An TCP connection requires IP packets going from the client to the server and IP packets going from the server to the client.
Ok, now think of each IP packet as a letter that you drop in a mail box and that the Post Office carries to its destination. Traceroute shows all the stages on the journey of the letter from your dwelling to the recipient's dwelling: the mail box it's dropped in, the town post office, the district sorting office, the regional mail hub, etc., until the letter reaches the recipient's mail slot. This is basically what you see when you watch the progress of a registered tracked parcel with DHL/UPS/...
In this example, the first two hops are called ….xs4all.net; they're clearly from the snapshot author's ISP. The next few lines are from WV Fiber, which operates international transit lines. I don't know who as30217.net is; probably an ISP for datacenters. The final two machines are from Wikipedia.
IP routing is completely transparent to higher-level protocols such as TCP and a fortiori all protocols built over TCP. In fact, traceroute has to play some tricks to obtain the information at all.