Why proactively market?
You hope your blast e-mails, your trade show booth, your ad, or your web page is so convincing that potential customers see that they absolutely need you, have to have whatever product feature you are highlighting, and will contact you. You hope to grab enough of their attention for them to self-filter from the masses and you luck into a few sales.
I recently read on SethGodin’s blog about a term coined by David Balter called 'scalejacking'. He defined this as trying to grab a lot of attention broadly and then letting the members caught in this ‘net’ filter down so you can profit. This is a weak approach and will be sniffed out more and more as customers get more cynical and self-regulating. Weak crap won't cut it in the world of product marketing anymore.
Think highly enough of your potential customers that you actually think about them and their needs and how your unique proposition will be received by them.