Jeffrey K. MacKie-Mason

Using Uncensored Communication Channels to Divert Spam Traffic (Download full paper)

Chiao, Benjamin and MacKie-Mason, Jeffrey K.

Published on: March, 2009

Abstract: We offer a microeconomic model of the two-sided market for the dominant form of spam: bulk, unsolicited, and commercial advertising email. Most most spam is advertising, and thus should be modeled as a problem in the market supply and demand for advertising, rather than the usual approach of modeling spam as pure social cost to be eliminated. We adopt an incentive-centered design approach to develop a simple, feasible improvement to the current email system using an uncensored (open) communication channel. Such a channel could be an email folder or account, to which properly tagged commercial solicitations are routed without any blocking or filtering along the way. We characterize the circumstances under which spammers would voluntarily move much of their spam into the open channel, leaving the traditional email channel dominated by person-to-person, non-spam mail. We show that under certain conditions all email recipients are better o when an open channel is introduced. Only recipients wanting spam will use the open channel enjoying the less disguised messages and cheaper sale prices, and for all recipients the dissatisfaction associated with both undesirable mail received and desirable mail filtered out decreases.

A Social Mechanism for Supporting Home Computer Security (Download full paper)

Rick Wash and Jeffrey K. MacKie-Mason

Published on: October, 2008

Abstract: Hackers have learned to leverage the enormous number of poorly protected home computers by turning them into a large distributed system (known as a botnet), making home computers an important frontier for security research. They present special problems: owners are unophisticated, and usage profiles are varied making onesize-fits-all firewall policies ineffective. We propose a social firewall that collects security decisions and both user and usage characteristics, and provides users with personalized information to assist with allow/deny recommendations. To succeed, a social firewall must deal with at least three user behavior issues: why contribute private information? why make effort to provide quality information? and, how to prevent manipulation by adversaries? We sketch an incentive-centered design approach to each problem. We provide an economic model and some analytic results for a solution to the fundamental problem: why contribute? We show that an excludable public goods mechanism can achieve a better outcome than a system without social motivators.

Economic Incentives (Download full paper)

MacKie-Mason, Jeffrey K.

Published on: January, 2000

The Case for Market-based Push Caching (Download full paper)

MacKie-Mason, Jeffrey K. Chan, Yee Man Womer, Jonathan Jamin, Sugih

Published on: November, 1999

Inducements to Advocacy: The Economist as Independent Expert (Download full paper)

MacKie-Mason, Jeffrey K. and Richard A. Pfau

Published on: January, 1999

Abstract: The appropriate role of the economic expert in antitrust litigation is to seek the truth, whereas the role for the attorneys is to seek the best possible outcome possible for the client. Yet the attorneys hire the economic experts, and the experts often work closely in many aspects of researching and developing the client's case. Can an expert economist provide an independent, professionally respectable opinion in this setting fraught with advocacy? We discuss the inducements to advocacy faced by economists who testify in antitrust proceedings, and ways in which a practicing economic expert might counter these inducements. We discuss two cases in which we have been involved to illustrate some of the important issues.

Biased Replacement Policies for Web Caches: Differential Quality-of-Service and Aggregate User Value (Download full paper)

MacKie-Mason, Jeffrey K. Kelly, Terence P. Chan, Yee Man Jamin, Sugih

Published on: January, 1999

Abstract: Disk space in shared Web caches can be diverted to serve some system users at the expense of others. Cache hits reduce server loads, and if servers desire load reduction to different degrees, a replacement policy which prioritizes cache space across servers can provide differential quality-of-service (QoS). We present a simple generalization of least-frequently-used (LFU) replacement that is sensitive to varying levels of server valuation for cache hits. Through trace-driven simulation we show that under a particular assumption about server valuations our algorithm delivers a reasonable QoS relationship: higher byte hit rates for servers that value hits more. We furthermore adopt the economic perspective that value received by system users is a more appropriate performance metric than hit rate or byte hit rate, and demonstrate that our algorithm delivers higher "social welfare" (aggregate value to servers) than LRU or LFU.

Using a Minimum Threshold to Motivate Contributions to Social Computing (Download full paper)

MacKie-Mason, Jeffrey K.

Abstract: Social computing systems collect, aggregate, and share usercontributed content, and therefore depend on contributions from users to function properly. However, humans are intelligent beings and cannot be programmed to behave; system designers must provide incentives to encourage users to contribute. We explore the behavioral consequences of one simple incentive mechanism: require users to contribute a minimum amount of information before they are granted access to the system. Users with a high marginal cost of contribution will stop using the system, but users with a moderate marginal cost will increase their contribution, frequently leading to greater benefits for everyone still using the system. Additionally, if contributions are collaborative and build upon each other, then existing contributors are likely to slightly decrease their contributions, leading to a more ’equal’ distribution of contributions. We show that this mechanism often leads to increased contributions, and provide concrete design advice for using this mechanism in social computing systems.