This article: Marketing or Sales: Which is most important? by C.J. Hayden is worth reading. She is addressing the interface between marketing and selling efforts -- and the importance of converting and 'closing' leads generated by the marketing process.
(This blog and my bi-weekly newsletter are 100 per cent marketing since we have nothing to sell on these pages. Is this stuff good for sales? Absolutely -- besides direct leads that are passed on to the sales team, I'm seeing plenty of signs that it is helpful in the recruitment process -- great candidates for sales careers in our organization read this blog before applying. But we still have to follow up, properly.)