Doubt on echo 1 >> /proc/sys/vm/drop_caches

[Abhishek Rane <abhishekrane gmail com>]

Hi there,
              I have a doubt whenever i do echo 1 >> 
/proc/sys/vm/drop_caches it drops the caches..I also see a "significant" 
change in the Memory stats of the Gnome system manager.I feel kinda 
happy but all i know about it is that it drops the caches.I want to know 
whether it is safe to do that?.Also will echo 2 or echo 3 make a 
difference?..and how can it be useful for a normal user like me who 
browses the net and stuff?