You can request WebMarketing123's 2017 State of Digital Marketing Report; earlier years: 2016 | 2015 | 2014 | 2012 | 2011
2017 Social Media Marketing Industry Report. The previous reports are also available: 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010.
The 2016 State of Social Business research report may be requested from the Altimeter Group. The previous reports are also available: 2015 | 2013
2016 Digital Marketer: Benchmark and Trend Report can be requested from Experian; previous reports: 2015 | 2014 | 2013 | 2012.
The Society of Digital Agencies recently released the SoDA Report, their bi-annual outlook on digital marketing.
A different State of Digital Marketing 2015 report comes from Smart Insights.
BlogHer released findings from their 2014 Women and Social Media Study.
Online Marketing for Professional Services Firms from Hinge Research Institute.
Ascend2 offers a library of Research and Reports for strategic outlooks on different e-commerce marketing approaches.
PowerReviews' 2011 Social Shopping Study, Brief 1: Consumer Research Dynamics, Mobile and User-Generated Content.
The Center for Marketing Research at the University of Massachusetts has a series of studies on social media adoption.
The Incite Group offers an annual report on Corporate Social Media to subscribers of their services.
Six New Segmentation Models to Understand Social Networks and User Participation from the Greater Than One strategy group.
A Framework for Social Analytics: Including Six Use Cases for Social Media Measurement, is a 2011 report from the Altimeter Group.
The Mobile Marketing Association links to various reports produced by member organizations in its Public Research section.
You can find a "Speed Summary" for many reports at Digital Intelligence Today.
And some studies have been summarized as Infographics by Lab42, a market research firm.