Microsoft announced today that it has completed transitioning user accounts from Hotmail to Outlook.com, providing those users with a modern and capable web email service. During the 6-week transition period, Microsoft moved hundreds of millions of accounts and over 150 petabytes of email data. And now they’re adding more features too.

150 petabytes is 150 million gigabytes. Yikes.

With all Hotmail users now migrated to Outlook.com, Microsoft says there are over 400 million people using the new service, with over 300 million of them coming from Hotmail. This includes 125 million users who access Outlook.com over the de facto standard Exchange ActiveSync (EAS) protocol with mobile devices.

Outlook.com has been pretty amazing all along, since the first preview release in summer 2012. Since then, however, Microsoft has consistently updated the service with new features, including the updated Calendar experience, a new Outlook.com app for Android devices, two-factor account authentication, many new international domains, and the preview version of Skype calling in Outlook.com.

This week, Microsoft announced two new features in Outlook.com:

Send messages from other email addresses. Yep, they’ve finally gotten rid of that horrible “on behalf of” silliness. You can now send email messages using Outlook.com that appear to come from other email services. That way, if you consolidate all your email accounts through Outlook.com as I recommend, no one needs to know anything changed. This new SMTP send capability is now available worldwide.

Deeper SkyDrive integration. While SkyDrive has always been “part” of the Outlook.com web experience, today’s update integrates SkyDrive more deeply than ever into the Outlook.com web email experience too. “When you're sending an email message, you can select files from your SkyDrive and we'll automatically turn those into the right thumbnails with links that have the right permissions tied to people that receive the email,” Microsoft’s Dick Craddock writes in a post to the Outlook Blog. “When you insert pictures from SkyDrive, you automatically get a beautiful photo mail. And it's easy to edit the message, and add or remove files and pictures right from the new message compose experience.  This new integration is starting to roll out today and will be available worldwide in the coming weeks.”

Amazing stuff.