Aegis did not disclose the value of the deal, but revealed that as of 31 December ICUC had gross assets of $1.4m (£845,000).
IProspect will leverage ICUC's community management platform and social media expertise for its clients, which include Gap, Converse and Burberry.
ICUC, which has 200 employees in North America, has clients including Chevron, Intel and Starbucks.
Jerry Buhlmann, chief executive of Aegis Group, said: "ICUC's market leadership and breadth of expertise in media intelligence and moderation services will boost iProspect's leadership across the digital performance spectrum.
"Beyond social media moderation, ICUC brings nearly a decade of astute social media understanding and intelligence to verticals ranging from entertainment and media to CPG and retail which fits in every respect with the next generation of social media services."
Aegis agreed a deal for Lithuanian media agency Creative Media Services UAB last week and on Monday confirmed it is in talks with Ipsos about the possible sale of Synovate, its research arm.