Google related tools:
http://www.google.com.hk/ggblog/googlechinablog/Google Blackboard
http://www.mattcutts.com/blog/ Matt Cutts’ Blog
http://www.google.com/support/webmasters/?hl=cnWebmaster Tools Help
http://www.google.com/support/websiteoptimizer/?hl=cnWebsite Optimizer Tool Help
http://www.google.com/support/googleanalytics/?hl=cn Analytics Help
http://adwords.google.com/support/aw/?hl=cn AdWords Help
https://www.google.com/adsense/support/?hl=cn AdSense Help
http://www.google.cn/trendsGoogle Trends
http://www.google.com/intl/zh-CN/analytics/Google Analytics
https://adwords.google.com/select/Tools AdWords Tools
Baidu related tools:
http://www.baidu.com/search/guide.html Web Search Help-Webmaster FAQ
http://tools.beijing-seo.org/baiduindex/Default.aspxBaidu keyword analysis tool
http://www.zhuici.com/ Zhuici.com
Query tool:
http://tool.chinaz.com/Webmaster Tools
http://www.flashplayer.cn/ Guanqi Webmaster Tools
http://www.ranknow.cn/ Ranknow Website Assistant
http://www.ranknow.cn/tools Ranknow tools
http://www.archive.org/Website History
http://www.meta.cn/ META China
http://www.alltheweb.com/ Alltheweb engine
http://alexa.chinaz.com/ ALEXA ranking query
http://baidu.buscx.cn/go.php Baidu included query
http://siteexplorer.search.yahoo.com/Yahoo backlink and inclusion query
http://www.majesticseo.com/ Majestic anti-link detection
http://check.linkhelper.cn/Friendly link detection
http://www.go9go.cn/Friendly link exchange
Detection tools:
http://jigsaw.w3.org/css-validator/ W3 CSS detection
http://validator.w3.org/ W3C standard detection
http://yueshui.net/HA_Xenu1.3.6.rarDead link detection (Xenu)
Website ranking:
http://www.alexa.com/Global ALEXA ranking
http://cn.alexa.com/Chinese ALEXA ranking
http://www.google.com/adplanner/static/top1000/Global 1000 website rankings
http://top.chinaz.com/ Chinese website rankings (can compare PR value)
wainshine