If you’re reading this list, you probably use Gmail. Before, you had to keep a Gmail window open, adding to the chronic tab clutter that bedevils many Chrome users. That’s why Google Mail Checker is so helpful. It adds a small Gmail icon on your toolbar and tells you how many new emails you have as they come in. When you feel like actually checking your email, just click the icon and Gmail will open in a new tab.
Link: Google Mail Checker