Few industries have suffered more severe disruption by digital technologies than news and journalism. Traditional content creators, such as newspapers, are witnessing their geographical monopolies dissolving into the globally competitive Internet and some of their most important sources of revenue, such as classified ads, migrating to specialized online marketplaces like eBay and Craigslist. User-generated content, such as blogs and online reviews, has increased the supply of content that often competes head-on for readers' attention with professionally produced content. As if the previous changes were not enough, an equally disruptive transformation is currently underway in these industries. The overwhelming amount of content available online has increased the importance of curation and aggregation, that is, of interfaces and services that help readers filter and make sense of the subset of content that is important to them. Historically such functions used to be the realm of professional editors: editors not only commissioned the production of content but also decided what content would be included in a newspaper or magazine issue and how it would be organized. Web technologies allow this important function to be unbundled from content production. Specifically, the web's ability to place hyperlinks across content has enabled new types of players, commonly referred to as content aggregators or web portals, to successfully enter the professional content ecosystems, attracting traffic and revenue by hosting collections of links to the content of others. Aggregators produce little or no original content; they usually provide titles and short summaries of the articles they link to (Figure 1). Well known aggregators include Google News, the Drudge Report and the Huffington Post. Table 1 provides a more extensive list of examples. Facing severe financial pressures, some content creators have turned against content aggregators, accusing them of "stealing" their revenues by free riding on their content. Other market actors point out that in today's "link economy", the links bring valuable traffic to the target nodes. Therefore content creators should be happy that aggregators exist and direct consumers to their sites. Key aggregator executives, such as Google's Eric Schmidt, assert that it is to their interest to see content creators thrive, since the value of links (and aggregators) is directly related to the quality of content that these point to. A central aspect of the debate focuses on the complex economic implications of the process of placing (for the most part) free hyperlinks across content nodes. The main argument in favor of aggregators is that, if links are chosen well, then they point to good quality content; as a result, they reduce the search costs of the consumers, which may lead to an aggregate increase in content consumption and to more traffic for higher quality sites. The main argument against aggregators is that some consumers satisfy their curiosity by reading an aggregator's short snippet of a linked-to article and never click through to the article itself. In fact, the question of whether aggregators are legally permitted to reproduce an article's title and snippet without obtaining permission from (and possibly paying) the content producer is still unresolved. Even though there is still an open question of whether the current generation of news aggregators is beneficial or harmful to the content ecosystems (Dellarocas et al. 2010), we believe that the ever-increasing volume of available content makes some form of aggregation an inevitable and valuable component of every content ecosystem. The key question, therefore, is not whether aggregators should exist, but rather how the partly symbiotic and partly competitive relationship between aggregators and content creators can be optimized for the benefit of both parties. In an attempt to provide initial answers to these questions, we conduct a series of field experiments whose objective is to provide insight with respect to how readers distribute their attention between a news aggregator and the original articles it links to. Our experiments are based on manipulating elements of the user interface of a Swiss mobile news aggregator. We examine how key design parameters, such as the length of the text snippet that an aggregator provides about articles, the presence of associated photos as well as of other related articles on the same story, affect a reader's propensity to click on an article, the amount of time that the reader spends on that article after clicking, and the amount of time that the reader spends on the aggregator. Gaining a firmer empirical understanding of these relationships will be valuable not only for aggregators seeking to optimize their own traffic patterns, but also in terms of informing the public discourse between aggregators and content creators on the need for equitable profit sharing agreements between the two parties. Our results indicate that there is, indeed, a degree of substitution between the amount of information of a news article that is displayed on news aggregators and the cumulative time that readers are likely to spend on the original article site. We found a negative relationship between an article's snippet length on the aggregator and the probability that a user will click the link to the original article site: the longer the snippet, the lower the click-through rate. Moreover, we found a positive relationship between an article's snippet length and the amount of time readers spend on the aggregator until they decide to click on the linked article. Interestingly, the presence of an image has the same effect to that of increasing the snippet length on the article's click-through rate: it is associated with a decrease in click-through rate and an increase in a reader's average decision time. We also found that when there is a click-through, the amount of time spent on the original...