The system I'm working on got press via the local news a few times (they love running scrappy tech startup stories, so it was one 30 second Channel 5 type interview and a news story). There wasn't a direct bump in sales because of it.

Everything I work on is B2B so 100% of sales are done via a conversation and not someone landing on the site and clicking "sign-up" so YMMV. The news articles was only important to solidify ourselves as a legit operation, and not really for the press it generated.