I don't think most people input keywords directly into the address anymore. This also only works if the user has a certain piece of software installed. Do you know what software that is? Many times (and I don't know this company) it's spyware which later gets removed.
15 million users is not that many worldwide. Its not even that many in just the U.S. - there are better places to spend your money.
I just spoke with them today. Pretty aggresive selling. The guy had some semblence of what he was talking about but chose to blur the lines between reality and sales-pitch. For instance, having me search for a kw on Ove's tool (144K searches last month) and then equating those searches to traffic into my website. Sort of skipped the part about the users actually needing to click on the advertisement to get to my website.
Some company today didnt even bother to explain themselves they wanted to me to watch a flash presentation with them on the phone so id understand.... SearchRocket is who they were. And their demo shows a search for tires on google bringing up iFrame of some company. Stay clear of them too.