Firstly, they will buy the best research available on their target market. They will continually test their market assumptions against reality. They know that what customers think and need today will not necessarily hold true in 6 months' time. The Marketing Director needs to be a Board Member. And there also needs to be a Sales Director on the Board.
Marketing is long term, sales is short term.
If marketing must be teamed with another function, make it research and development maybe, but never sales. The UK recession has brought about the downsizing of many UK subsidiaries of foreign based IT companies, and they have become just sales offices. A successful IT marketeer in the UK office of a foreign high tech vendor will have to be skilled at dealing with foreign HQ management. He, or she, needs to have the knowledge and people handling skills to persuade foreign management to allocate sufficient budget and allow local implementation flexibility. He, or she, must be strong enough to resist the pressures imposed by the foreign HQ to implement marketing programmes and messages which are inappropriate to the local geography.