Microsoft begain rolling out Hotmail Wave 4, you might see new features in your inbox, features like new Sweep menu, freshly integrated Office Web Apps, huge new attachment limits up to 10 GB using SkyDrive, and ability to create & send photo albums right from Hotmail.
"You might be wondering why everybody doesn't get the new version immediately. Well, Hotmail servers are grouped into clusters, and we've hundreds of clusters. We start by upgrading a single cluster, wait to make sure that it's running smoothly and that we didn';t miss anything during testing, and then we continue on to next cluster. If we find a bug, we';ll fix it before continuing further, and give that fix to everybody who has been upgraded so far. That way, we release the highest quality code as we proceed, and we can minimize downtime for everybody. Accounts are assigned to clusters to best balance our total account load, not by country or by tenure of the account, so each account is as likely as the next to be upgraded. Given this, we can t move any individual accounts up or down the migration line," revealed Microsoft.