As part of the OpenSocial 0.8 release , we're proud to announce a Developer Only release of MySpace Custom Application Activities. App Activities allow developers to get app-related events and messages into the Friends Update feed that appears on a user's home page.
What does a custom app activity event look like? Here's a portion of my Friend Update feed:

As a developer, you'll be able to define your Activity Templates and then raise events using those templates in your OpenSocial applications. If you want to skip the chit-chat, you can get started right away by going to the template editor.
A templatelink appear under each app on the developers My Apps section. See screen shot below:

App Activities Key Limitations:
1. Only developers of the apps can successfully raise activity events.
2. Only developers of the apps will see the activity events in their Friend Updates feeds.
3. Apps can raise activity events *without* triggering the Activity Permissions pop-up
- Point #3 is important because when Activitiesgo live, users of the apps will get a pop-up asking for their permission to notify their friends about the activity. This should have implications in developer's design decisions on when and how frequently to raise activity events.
Limitations, Restrictions and Known Issues
There is a full list of limitations, restrictions and bugs on the Activities Forum.
Getting Started with the Editor
The template editor is your primary point of interaction for defining activity templates. The template editor allows you to define and preview templates, and provides sample JavaScript for use in your apps. The variables and media items are only used for previewing your events. Please see the Getting Started documentation for a full walkthrough.

Raising the event
The code sample below shows how to raise the event. (We are using some jQuery constructions here, but you probably be able to see what is going on).
function sentActivity(){
var params = {};
//tell which template we want to use
params[opensocial.Activity.Field.TITLE_ID] = "RateCar";
params[opensocial.Activity.Field.TEMPLATE_PARAMS] = {
"carModel": "Tesla Roadster", "starCount": "10" };
var activity = opensocial.newActivity(params);
//this will show a popup dialog asking the user if he really wants to sent the event. opensocial.requestCreateActivity(activity, opensocial.CreateActivityPriority.HIGH, opt_callBack);
}
function opt_callBack(response){
//only for developers, on a developers template we will give you some detailed error info back!
if (response.hadError()){
//using some jQuery magic
$("#status").append("<span style='color:red'>" + response.getErrorMessage() + "</span>");
}
}
We are looking forward to your feedback,
Marco, @nkur, Jitesh and the full MDP team.

