This visionary company was the pioneer that started to change the face of marketing and sales solutions from about 2001. 

Prior to Salesforce there really were only on-site or on-premise Sales and CRM solutions. The Salesforce.com system was delivered across the Internet, a pioneering move at that time. Salesforce was an innovator right from the start and has done much to develop the marketing and sales solutions market as it is now.

The Salesforce offering has many elements to it, from low cost small business systems right through to top level enterprise systems. 

Visit the Salesforce.com website for more information.

One consideration to bear in mind is that the origins of Salesforce is a system for the sales team. Tgherefore its support for the marketing function might not be as strong as systems that are designed for marketing.

However, there are many email marketing systems that have connectors into the Salesforce.com system to offer enhancved functionality where they perceive a weakness in the Salesforce offering.

Essentially you work out what you need and you choose your system to suit.