There's no better proof of an app's popularity than add-ins that extend its power. Since Gmail is web-based, add-ins for web browsers can extend it in various ways. Free downloads can help you manage address books, maintain to-do lists and simplify mailing chores such as sending attachments.
As Gmail has evolved, it has made many add-ins obsolete by incorporating their functions. Some simply no longer work properly. Here though are 10 tools that could still improve your Gmailing experience.