1. The easiest way to check the spelling of a text, even if you write in Polish. You don't need an application like Office, or a plug-in for your browser.
2. The simplest way to view Office documents and PDF files online.
3. The fastest way to download attachments. If you receive documents or text files, downloading all the attachments as a single zip saves you time and bandwidth.
4. The webmail service that uploads your attached files while you write your email. Another time saver.
5. Your favorite instant messenger. If your friends use Gmail or Google Talk, you can reply to their emails using Gmail Chat or start a conversation from your browser.
6. A basic antivirus. If you don't have an antivirus or you can't access an online detection site, upload the suspect file to Gmail (if it's an executable, rename it).
7. An MP3 player with plenty of storage, but without too many features. Or even an online extension of your hard drive.
8. A feed reader that shows random headlines from your favorite blogs and news sites, while calling them "web clips".
9. Your uber-mail account, where you forward messages from your other mail accounts, organize them and reply to them.
10. Your assistant. Gmail detects in your messages information about packages and lets you track them, maps addresses, and makes it easy to add events in your calendar.