I was was getting this on my Evo 4G starting about 5-6 months ago. I just upgraded to the new Evo 3D a week ago yesterday. When I restored all my apps that I backed up from my 4G to the new phone, the problem followed. This told me that it was indeed an app. Reading these many posts, it doesn't look like it was any ONE SINGLE app. I got the spam this morning and left the star up in my notification bar.

I have been posting this info wherever I can. After doing some research into this (*). This is due to a spam tool called 'airpush' that is employed by a number of Apps developers. You can download an app called AirPush Detector which will identify which of your apps is running 'airpush'

* Why because:
a) I was infuriated at status alerts being sent without my consent and beyond my control to switch off
b) The app wasn't even being used at the time of alerts
c) My children use my device and I don't want them seeing cheap smutty adult spam!!!

Here is a long to the detector: https://market.android.com/details?id=com.brosmike.airpushdetector

I've been getting these as well. After finding this post I installed the detector and identified the offending app.