Unfortunately, details are slim. The report says that iCloud will be adding the ability to share photos and videos with others via iCloud, and also allow for commenting on shared items. There is no reported integration with any outside social networks, so it's unclear if photos and video would be able to be shared on Twitter (we'd say it's likely), Facebook (possible), or Google+ (yeah, right!).
iCloud is also said to be getting an update to allow users to view Notes and Reminders through the web portal. Of course, we'll likely get all this info at WWDC in just under a month.