The notifications are displayed in the status bar which acts like a button to open a larger view to show all new (and maybe old) notifications. And since it is rumored that iOS 5 will offer a deep Twitter integration the "leaked" screenshot shows Twitter mentions, with a very slick status bar icon, too.

The single most interesting in my opinion is the stacking of notifications seen in the screenshot. E.g. that the notifications  "You were mentioned by @iclouddev" and "You were mentioned by @mashable" would be aggregated and shown as a plain "2 mentions" in your status bar. This will make it easier to prevent user spam and still inform users about granular actions. (This was formerly available to app developers on Facebook, know as template bundles. Good times.)

P.S. Here is the best looking third party notification system I could find: MobileNotifier beta3, "Copious Corn Flakes"

This is great news for developers. Soon you don't have to wait weeks until old versions of apps disappear. This makes it easier to develop and change features with much less effort on providing backwards compatibility over long periods.

Let's take a look what the Big Three of the cloud business bring to the table for developers.

Amazon AWS

Amazon is a long time player in the cloud business with its Amazon Web Services. It provides cloud storage via S3, a non-relational datastore called SimpleDB and many more services from content-delivery network to  e-commerce and virtualization. Amazon even offers a hosted environment for MySQL Databases. All in all very customizable and covering most of the infrastructure you would need to run a website or webservice. I personally  run projects on Amazon AWS.

Micosoft Azure

Microsoft introduced Azure in 2008 and became an important  competitor to AWS. It started with a different goal thought: providing a Platform-as-a-Service (PaaS). This enables developers not to worry about the architecture and virtual instances their software runs on and scaling it accordingly. In contrast to Amazon AWS Azure only offers Microsoft products, SQL Server and Windows Server etc naturally providing an easy integration with most of them. If you want to read more about Azure vs. AWS: http://cloudtimes.org/amazon-aws-vs-microsoft-azure-part-1/.

Google App Engine

Google's App Engine can also be described as a PaaS. Providing a framework to run JAVA and Python applications using their own infrastructure like BigTable Database and only allowing to communicate with the outside world over HTTP/S, essentially eliminating the ability to use existing infrasturcture like MySQL databases etc. An advantage of the App Engine platform is that it is free up until a certain threshold (e.g. CPU time per day, bandwidth and storage used).

Where does that leave iCloud.

So... will Apple  really enter that space with their iCloud offering?

What do I think? I don't think Apple will offer such developer centric cloud services as Amazon, Google and MS are. Why? Because in my opinion Apple will be better off tackling the problems which are not solved yet in a good way, like OS integration with the Cloud and moving significant parts of your local data online - like music. Infrastructure for running webservices in the cloud is already advanced. Apple will want to solve a problem, and thats making it easier for all consumers to make use of cloud services, not developers per se. A strong hint to the customer focus is that customers will have to pay for iCloud (rumors say $25 per year), not developers.

So where does that leave this blog with it's iCloud developer focus? I think iCloud will provide many opportunities to make use of Apple's customer centric cloud services by enabling other apps on iOS and Mac OS X Lion to make use of them. Examples could be cloud calender integration, cloud photo libraries and even syncing app states and information across all devices. Enabling the developer to focus on great products rather than syncing information over a myriad of services.

Well. we'll know for sure on monday.

Let me know your opinion about what iCloud could mean for developers in the comments below.

iCloud rumors: may be free to Lion users, movies and TV up in air