<p>What does the SQL Action keyword do?  Can I use this keyword in a trigger and determine if the trigger was called by an Insert, Delete or Update?</p>

No, you can't use it for that. But you can look at the
Inserted and Deleted
tables to see what happened.
A vary basic example would go something like this:
```
```
If exists (select * from inserted) and exists (select * from deleted)
    --Update happened
If exists (select * from inserted)
    --Insert happened
If exists (select * from deleted)
    --Delete happened
Else
    --Nothing happened
```
```
Realistically, though, it just depends on what you need to do.  In some cases, you might just end up joining on these tables by primary key and do various things.
If you post more details in your question about what you're attempting, though, it'd be easier to give a more specific response.