CareerCup

client side
1) caching
server side
1) mirroring

use content delivery networks (akamai etc.)

increase the RAM size :)

increase the RAM size :)

There can be so many things. from bandwidth to high server load to incorrect algorithm

Congestion in network,traffic overload or there might be too many objects in the web page to be retrieved etc..

write a test client which accesses the web service. Profile the complete system flow when the web service is accessed to find the bottleneck [some possibilities: high network latency, poor cache hit ratio, db access latency (if applies), too many context switches- run different servers(app/web/db) on different machines]