After google moved their service from china mainland to hongkong, I can't access google.com or google.cn from mainland anymore. I always get redirected to google.com.hk. Based off my experience with google.com.hk, it shows more noise information than google.com and google.cn. Because in most cases, results in transitional chinese aren't what I'm looking for.
To force the browser using google.com, we can visit the url http://www.google.com/ncr. After it has been visited once, all subsequent requests for google.com won't be redirected to google.com.hk anymore. Hooray!