Icon/Status Bar Notifications?

As I mentioned in my last thread I just dropped iPhone yesterday for a Blackberry Tour (great phone) and one of the handful of things I miss from the iPhone are Status Bar Notifications. By default it seems SMS/Email and Alarms all get one but I havent run across a single third part app to have one yet. Ideally Id like an icon to pop up for RSS and Replies/DMs from Twitter. Also, Ive seen a few themes that offer weather info somewhere but again it'd be nice if one of the weather apps put that up there with the SMS notifications.

I guess Im asking, is this a limitation of the OS itself or just not a common request from BB users? And if its not a limitation are there any apps that use it or an app specifically designed to poll other apps and create those notifications itself? TIA

Facebook/Myspace/BBM all throw icon notifications in the status bar. There are other apps, but its based on the developer. It is however possible to do this.

Ahh okay, like I said Im new to all this so I figured it might just be the case I hadn't run across any apps to do it. Be nice if there was an app though that could pull data from others and create the notifications for those that choose not to do it.