Microsoft is opening up Office to developers unlike ever before. Earlier this year, the software company announced plans to bring third-party apps to Office 365, and now that program is being extended to Outlook.com. A new suite of APIs will give developers tools to hook into Microsoft's webmail service and add features to everything from the calendar to the compose screen and contacts. While we won't see the fruit of this effort for some time — the apps will first launch next spring — the program holds some exciting promise. Developers could come up with some truly useful apps that plug into not only Outlook.com, but also the rest of the Office 365 suite, including Word, Excel, and PowerPoint. And these apps will work cross-platform, according to Microsoft. Let's hope developers come up with some neat ideas.