Most startups i read of here, try succeeding in getting famous with a service known by millions of people. But, the market for startups trying to pitch products to well-established companies is not only big, it's also quite worth the effort, compared to direct-marketing. In most of the cases, startups don't have financial resources to reach out for residential customers, no matter how interesting your product might be (ok, you still might dream about succeeding like $youtube, $facebook, $whatever, but reality is you need some revenue to pay your rent, regardless what enthusiasts tell you.. and they won't pay your rent, unless they sign some investment thing - at least, here in Europe we tend to think like that).

However: large corporates often either lack innovation, or they try to lower costs by implementing something which is open-source. There is your chance. Go implement something based on open-source which is competitive to some commercial product, and you'll see you can sell for 1/5 of the price of big vendors.... and a lot of companies are really sick of being dependend of big corporates like Cisco, Nortel, whatever... you "just have to get your foot into the door" of such companies... and for this task, you have to have a great sales person.... you don't make it as a technical kind of person... I tried it... forget it... it's a completely different world... the important thing is: respect it... these sales-guys sell your late grand-mother, but they keep you going... No-one on the street will ever recognise you, and no-one on the street will have heard of your company, but does that really matter if you deliver to a big corporate which pays you some ten thousands of dollards a month to satisfy THEIR customers? Think about it, before wasting just another 10 men months to something RESIDENTIAL customers might like.