What differentiates these different specialist positions?

I’ve been going through Coroflot, design firm websites and have yet to come up with any clear distinctions on the different jobs titles that get posted. Are they just ‘tags’ to differentiate amongst focus areas or actually seperate job functions in a design studio?

Designer

Design Researcher

Design Strategist

Engineer

Now, t he first and the last are easy, but with the increasing fragmentation, (there are lots more I’m sure if I look) I’d like to be able to articulate these functions in the design process far more clearly. What do you say are the roles played by the designer, researcher and strategist in the design process and how do they differ from each other? I’ve written a little more about it here http://sizematter.blogspot.com/2006/02/specialist-jobs-or-design-process.html