No abstract

Abstract. Click fraud-malicious clicks at the expense of pay-per-click advertisers-is posing a serious threat to the Internet economy. Although click fraud has attracted much attention from the security community, as the direct victims of click fraud, advertisers still lack effective defense to detect click fraud independently. In this paper, we propose a novel approach for advertisers to detect click frauds and evaluate the return on investment (ROI) of their ad campaigns without the helps from ad networks or publishers. Our key idea is to proactively test if visiting clients are full-fledged modern browsers and passively scrutinize user engagement. In particular, we introduce a new functionality test and develop an extensive characterization of user engagement. Our detection can significantly raise the bar for committing click fraud and is transparent to users. Moreover, our approach requires little effort to be deployed at the advertiser side. To validate the effectiveness of our approach, we implement a prototype and deploy it on a large production website; and then we run 10-day ad campaigns for the website on a major ad network. The experimental results show that our proposed defense is effective in identifying both clickbots and human clickers, while incurring negligible overhead at both the server and client sides.

Abstract. Building a mobile user interface can be a time consuming process for web site administrators. We present a novel approach for adapting existing websites to the mobile paradigm. In contrast to existing technologies, our approach aims to provide a trio of functionality, ease of use, and scalability for large web communities. A site administrator visually selects objects within a web page, and assigns one or more attributes to page objects from a rich collection of pre-defined page modifications. Our proposed system then generates code for a multi-session, php-based proxy server to provide dynamic mobile content adaptations based on the attributes selected. The modifications encapsulate complex page interactions and provide a simplified interface to mobile users. The proxy server is augmented with a highly efficient and standardscompliant browser residing on the server to interpose on behalf of a resource-constrained mobile client. Adaptations such as pre-rendering of content can be cached and shared across users to amortize load. We build a prototype and evaluate its efficacy on a complex web application driving a busy online community with nearly 66,000 members.