2014 has already been a year of fascinating milestones for digital marketers. Earlier this month, we celebrated the 25th anniversary of the World Wide Web -- the foundation that makes our connected world possible. Facebook and Twitter both celebrated birthdays this spring, reminding us how the explosive growth of social media has changed the world in just a few short years. And now, we celebrate the 10th anniversary of Google's webmail service, Gmail.

Unlike the web, Facebook, and Twitter, Gmail was not the first of its kind. In fact, it was a relative latecomer to the webmail party. Gmail's objective was not to create a totally new way of communicating, but to make radical improvements to the existing webmail model. And the last ten years leave little doubt that they've succeeded.

To recognize the innovation and influence of Gmail, we've compiled a collection of insights from five email professionals. Their essays include memories from the early days of Gmail, their perspective on how it has changed the email industry, and even a few thoughts on what happens next.

Here's a preview of what you'll find in Celebrating Gmail's 10th Anniversary:

• Top 10 Innovations, Courtesy of Gmail
• Leader in Inbox User Experience
• Gmail's 3 Greatest Contributions
• 10 Ways Gmail has Changed Email
• Reflections on Gmail, Then and Now

Click here to read what the experts have to say about Gmail's 10th anniversary -- and share your own thoughts in the comments below.

Here's to the next 10 years. Happy birthday, Gmail!