Some ISPs give you a static IP to your account.
However, no the first two sets merely identify the ISP.
ISPs purchase a certain range of IP addresses to hand out to their customers.
Eg doing a WHOIS on my ip shows this:
inetnum: 118.93.0.0 - 118.93.255.255
netname: IP-VFNZ-BROADBAND-2
descr: Dynamic IP allocation pool for broadband services
This shows that any address in the 118.93.*.* range belongs to my ISP, Vodafone New Zealand.
Websites track who you are by using 'cookies' to store your information