The board rooms of digital media and commerce companies were the busiest among all marketing, media, technology and service companies during the first half of 2012. Digital media and commerce firms inked the most merger and acquisition and investment deals of any segment in the category, according to investment banking firm Petsky Prunier LLC.

Digital media and commerce companies announced 515 merger and acquisition and investment deals in the first half, with a total value of approximately $13.5 billion.

Within that, 331 were investment deals with a total value of $4.4 billion. E-commerce, social media/apps and mobile content/apps comprised 68% of the investments within the digital media commerce segment. These investments included Microsoft Corp.’s $300 million investment in Barnes & Noble’s Nook digital reader and content business, and Rakuten leading a $100 million round of investment for social network Pinterest. Barnes & Noble is No. 32 in Internet Retailer’s Top 500 Guide. Rakuten is the parent company of Buy.com Inc., No. 36.

184 of the 515 deals during the first half were mergers or acquisitions with a total value of $9.1 billion. E-commerce, social media/apps and niche content comprised 53% of the total transactions during the first half within the digital media and commerce segment. These transactions included Facebook’s $1 billion acquisition of photo-sharing service Instagram and Wellpoint Inc.’s acquisition of 1-800 Contacts. 1-800 Contacts is No. 75 in the Top 500 Guide.