I will address some of the structural issues associated with marketing and sales functions. Others have identified that the structure of the sales and marketing function may not be the best way to address the underlying human and talent resource issues.
In the traditional context the marketing function is the process through which new leads are identified and sales is where they are converted to customers.
(Marketing and marketing operations has expanded considerable and involves many more functions which can include the ongoing cultivation and promotion of the brand, strategic positioning, research, business intelligence, public affairs, public relations, and even pricing. That does not significantly change the outcomes -- but it does increase in relative importance marketing in todays market.)
As you map out your customer acquisition and support functions into defined steps you can segment these functions into roles which are prescribe to different people.
In this way you could end up with someone that generates interest, someone who qualifies and provides initial educations, and then a sales specialist that moves the customer to close, and a closer that earned the final business, with then an account manager to ensure the customer gets what they purchased and continues to be your customer.
It is seductive to do this based on what your internal business drivers are -- what makes sense to you and your operation. this can lead to a disastrous result if it does not match how the customer would like to experience your business. for example if you are in and industry where strong personal relationships leads to long established business relationship then the initial sales person may need to be the primary contact for the client throughout their time with you.
The rotating of a customer server person so that the clients gets the benefit of the different people with your company -- and establishes a relationship with the company as a whole can be extraordinarily powerful. The key to making this work is open and clear communications with the client supported by a robust CRM that ensure nothing falls through the cracks during the transfer. Having a person- - like you -- that is seen as the constant, and someone they can go to if they experience a problem is essential as well.
Strive to build and support a close relationship between your clients and the company-- close does not mean exclusive. Provide multiple communication avenues for the client to communicate with your company. You, a sales executive -- but others as well. An adoption expert could reach out to customers on a regular basis about their adoption of the tools. The CFO could reach out to discuss how they are experiencing the ROI of your service. A member of your production team could reach out regularly providing feedback on what customer generated change request have been acted upon and why. Leverage blogs and Twitter, newsletter, phone calls and meetings.
Build and maintain full relationships which transcend rather than replace the close contact with the customer support team.