This study explores the role of social media in social change by analyzing Twitter data collected during the 2011 Egypt Revolution. Particular attention is paid to the notion of collective sense making, which is considered a critical aspect for the emergence of collective action for social change. We suggest that collective sense making through social media can be conceptualized as human-machine collaborative information processing that involves an interplay of signs, Twitter grammar, humans, and social technologies. We focus on the occurrences of hashtags among a high volume of tweets to study the collective sense-making phenomena of milling and keynoting. A quantitative Markov switching analysis is performed to understand how the hashtag frequencies vary over time, suggesting structural changes that depict the two phenomena. We further explore different hashtags through a qualitative content analysis and find that, although many hashtags were used as symbolic anchors to funnel online users’ attention to the Egypt Revolution, other hashtags were used as part of tweet sentences to share changing situational information. We suggest that hashtags functioned as a means to collect information and maintain situational awareness during the unstable political situation of the Egypt Revolution.

Despite the growing body of research on creativity in team contexts, very few attempts have been made to explore the team‐level antecedents and the mediating processes of team creative performance on the basis of a theoretical framework. To address this gap, drawing on Paulus and Dzindolet's (2008) group creativity model, this study proposed team creative efficacy, transformational leadership, and risk‐taking norms as antecedents of team creative performance and team proactivity as an intervening mechanism between these relationships. The results of team‐level regression analyses conducted on the leaders and members of 103 Korean work teams showed that team creative efficacy and risk‐taking norms were positively associated with team creative performance. Furthermore, the relationships between team creative efficacy and team creative performance and between risk‐taking norms and team creative performance were mediated by team proactivity. These findings offer new insights regarding the antecedents and the mediator of creative performance in team contexts and important implications for theory and practice.

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a b s t r a c t JEL classification: G14 G31We document that corporate investment contributes to stock liquidity. This study demonstrates a positive relationship between abnormal corporate investment and stock liquidity in the cross-section. Moreover, stock liquidity improves more apparently for firms with financial constraints. Our robustness check confirms that the existing regularities cannot explain the current finding. This analysis suggests that corporate investment decreases the risk of a firm and that a change in the risk affects the behavior of a market maker, leading to an increase in stock liquidity. (M. Kang), wwang24@csuohio.edu (W. Wang), cyeom73@ehanyang.ac.kr (C. Eom).1 Our robustness analysis shows that higher corporate investment leads to lower return volatility, that is, lower risk. Therefore, corporate investment decreases the risk of a stock, which could be due to either idiosyncratic or systematic risk or both.2 Brunnermeier and Pedersen (2009) propose a differential effect of the market risk on high-and low-risk stocks while both Comerton-Forde et al. (2010) and Nagel (2012) empirically demonstrate that high-risk stocks are more prone to market-wide liquidity shocks.http://dx.