Hi, my previous question had different errors when trying to setup this same result as a Formula field, now I'm doing it through Workflow Rules / Field Updates and experiencing different error messages.  It all seems to boil down that I can't check to see if a Text field is null(blank) using the "ISBLANK" logical unit.  I don't know why that would be an issue, as the ISBLANK function is supposed to work with Text fields as per the online help guide.  

Right now my formula looks like this:  

IF(ISBLANK(Response__c ), "Responded", "Original")

And my error looks like this:

Error: Formula result is data type (Text), incompatible with expected data type (true or false).

Rather odd, I don't get it.