Action id vs Object id calrification

[Adam Venturella]

Just looking to confirm I have this distinction correct.

I'm just gonna use a Facebook feed as an example, since it's basically activities.

By querying the gaph API for feed:

https://graph.facebook.com/<userid>/feed

A List of activities will come back, status, link, photo, video, status etc.

The object id is clear for something like this,

lets assume it's something like: tag:facebook.com,{api_year}:{type}:{id}.

Now to be clear Facebook does not return id's like this, I'm just using that as an example of a data source. Their id's tend to be 1234_123456789 where the left of the _ is the userid and the right of the _ is the actual id of the status message.

interpolating the format above we could have:

tag:facebook.com,2010:status:123456789

But what would the Activity id look like? I'm assuming it's a similar but different id, possibly denoting the source of the activity?

tag:facebook.com,2010:feed:1234_123456789

The year portion is completely contrived, it means nothing in my examples, just assuming it it's more of a constant for disambiguation.

But note the portion after the year: "feed" vs "status|photo|video|link" of the actual object.

Or do I have this completely wrong and it's often the case that Activity Id's match Object Id's?  

Now, again, I'm sure this up to the vendor, based on how you could access the object again if need be, I am just trying to make sure I understand the difference between the 2 id's.