As I clear out my bookmarks, I keep coming across these great threads like this one on Designer News. I’ve reposted the top-voted comment by Ryan R., Lead Product Designer of Catalyz:

It’s a bit of everything.

I help to define:

• The experience and interface of our products
• The brand and marketing strategy around those products

What I’m actually doing:

• Wireframing
• Coding/Prototyping
• Creating style guides and patterns
• Conceptualizing product definitions and naming conventions
• Building requirements documentation with other engineers and designers
• Manning support and helping fill tickets to better understand our customers from the front-lines
• Any number of other things to help tie up loose ends on the design side