Do you know that you can use your mobile phone or tablet as a basic seismometer that can detect seismic activity while the phone is placed on a flat table.
As a website owner, you can easily know about the battery status (charge level) of your visitor's mobile phone or laptop with the Battery Status API.
Learn how to load the Disqus comments on demand when the users clicks a button. Alternatively, you can load comments when the user has read the article.
Learn how you can easily scrape the Reddit website using their own API and a little bit of Google Scripts. No programming or server required.
Learn how to use the address bar of your brower as a calculator with or without Google. You may even perform complex calculations here.
Old web browsers are not just insecure, they also pose a problem for web designers as they have to design sites while keeping the older versions in mind. If you like help people upgrade their outdated browsers, Pushup has created a script that can be easily integrated in any blog or website.
Wikipedia recently introduced a new auto-complete search feature that offers keyword suggestions in real-time as you type the characters in the Wikipedia search box.