Triggering on custom object update field data change

Absolutely, there is.  When you create a new custom object, you'll see a new set of triggers/filters in the right hand palette.  For e.g, I've a custom object named Survey1 and it magically adds the following triggers and filters - 

If it is not an object you're referencing, but a field, you can use the "Data Value Changes" trigger.  

I understand - but I want to make sure I can trigger on the data value change on the custom object, NOT when the object is first associated.

In Raj's example, I can trigger when a survey is first associated to a lead - ie "Added to survey1", with constraints.

Let's say the survey has a status picklist of "Started" and "Completed"

Say when the survey is started, it's associated with the Lead, I use your trigger of "Added to" to send them an email thanking them for starting the survey.

Now, when the survey is completed, the status is changed to "Completed". How do I trigger that? I can't use "Added to" anymore, because it's already added.

I need a "Survey1 is Updated" trigger - is that automatically created as well when a custom object is synced? Or is that feature only on the Opp object?

You'll have to track the state changes in a custom field using change data value.  

You mean a custom field on the Lead object directly? There is no chance that the trigger on the "Data Value Change" can peer into custom object's fields is there?

Has this custom object trigger been created?  I see that this was a topic 1 year ago but I am looking for the same thing.  I need a "Custom Object is Updated" trigger.  

Has Marketo find a resolution for this?

I would also find that trigger usefull. if there is an idea we can vote for please paste in here.

This feature is not only useful but is essential to implement one of our upcoming strategies. This should be included in the custom object package considering what we're paying for it.