Yes, absolutely. Marketing is part of everything. It's not a separate department or effort, it's a facet of every effort of a company. It's something that everyone, from product design to development should keep in mind.

I'm just running with the definition given to me by my marketing professor at my university's business school :)

Look at 37Signals. I contend that everything they do is marketing, even if it's not writing commercials or buying ads.