Smarketing is an alignment of a company's sales and marketing departments for better communication, more collaborative efforts, greater efficiency and, as a result, enhanced profitability.
Although the term itself is a buzzword, the approach it refers to is important for business sustainability. Intuitively, the two closely-related and interdependent business units should interoperate closely. However, in many companies, the teams aren't collaborative and there is little sharing of information that could enable better performance.
Marketing often focuses on customer targeting, product pricing and promotions, while sales is typically concerned with prospecting, sales funnel management, customer relationship management (CRM), upselling, Cross-selling and so forth. Sales and marketing alignment seeks to break down those barriers. Integration of CRM and marketing automation software systems is where many organizations begin.
See a presentation on smarketing by Dan Tyre of Hubspot: