Webmaster Tools (google.com/webmasters/tools/home?hl=en)
Of all the Google products, Google Webmaster Tools is the most versatile. It comes with loads of interesting features that can help you analyze website in myriads of ways. You can check whether or not your website has been attacked by virus or malware and you can also pinpoint spider crawl errors. It also offers HTML suggestions and some information on how to speed up the loading time of your website.
Google Chrome Developer Tools (blog.chromium.org/2009/06/developer-tools-for-google-chrome.html)
Testing and debugging your website in a web browser is the most convenient and easiest way of ensuring the stability and performance of a website. Being aware of this vital issue, Google Chrome has come up with an all new suite of effective tools that help you inspect different elements of your website meticulously before making it live. Some website developers even argue that this tool works even better than the popular Firebug.
Page Speed (code.google.com/speed/page-speed/)
As Google is passing more importance to loading time of a website, website owners are getting cagey about it since the ranking of a website is invariably associated with it. Page Speed is one such tool that lets you speed up your website by trimming redundant things as far as possible. You just need to install this amazing tool in your web browser and it will analyze your website automatically and then will show you the results.
Google Code Search (google.com/codesearch)
You are writing a mail function but it is not working somehow. Now, do not bang your head against the table rather do some searches in Google Code Search to find out what is wrong with your written codes. Google Code Search finds out results from different publicly available sample codes and it comes with an advance and intuitive search interface that will let you specify your search queries specifically.
Google Website Optimizer (google.com/websiteoptimizer/b/index.html)
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