I'm sorry if you mis-interpreted my response. I would expect the response time to increase with the distance from our server on the East Coast - nothing to do with Korea or any country in particular. I use the bookmarklet myself with Firefox on Ubuntu with the same performance as on Windows. Are you using a virtual machine to run Ubuntu? What type of networking are you using - NAT or bridged? Does the bookmarklet work okay on Firefox on Windows? If so, the only difference would be the Ubuntu setup.