Against a background of the low engagement of small to medium-sized enterprises (SMEs) in e-business, this chapter investigates the impact of e-aggregation applications, provided by emerging vertical application service providers (VSP), and defined as "an e-business application, promoted by a trusted third party, which engages a significant number of SMEs by addressing an important shared business concern within an aggregation". By conducting quantitative surveys of four aggregations of SMEs using these applications (users) and comparing these results with similar enterprises who are not (non-users) the research takes a deliberate SME perspective.