This thesis is a mixed methods analysis of the use of new, interactive web campaign techniques, often referred to as Web 2.0, by constituency level campaigns at the 2010 UK General Election. It has two main objectives: measuring the adoption of new web campaign techniques amongst constituency campaigns and assessing the influence of different factors on campaigns' propensity to use interactive campaigning. Drawing on previous work on parties' use of technology, this thesis tests a socially shaped explanation of adoption, hypothesising that the offline campaign style will be a strong influence. This contributes to the wider debate about election campaigning online by using an analytical framework of traditional and modern constituency campaigning that contextualises web campaign elements within the campaign as a whole. Data to test this hypothesis comes from a diverse range of sources. A national survey of election agents (ESRC Electoral Agent Survey 2010) is used to measure the offline campaign style of campaigns and their adoption of Web 2.0 campaign sites. Content analysis data from a subset of regional campaigns is then used to assess the extent to which campaigns actually used specific interactive features across a range of platforms. Finally, the findings of these analyses are triangulated using qualitative data collected in interviews with campaigners following the election. The findings of this work show that despite the rapid adoption of Web 2.0 sites, campaigns have not fostered the kind of interaction associated with an architecture of participation. The drivers of Web 2.0 adoption are more complex than originally envisaged, whilst social shaping explanations are relevant, statistical models leave much of the variation in adoption unexplained. In conjunction with the accounts of campaigners collected through interviews, this strongly suggests that researchers must consider more intangible factors such as the perceived symbolic and instrumental value of web campaigns alongside social factors when attempting to explain the adoption of Web 2.0.