Last spring a faculty member asked me to find theirh-index, collect the Impact Factor (IF) for all the journalsin which they were published, and compile the numberof citations each of their articles had received. WhenI presented the results, they insisted their work was moreinfluential than what the metrics suggested. I explainedwhy IFs for specialized journals were lower than moregeneralized publications such as Science or Nature, andwhy citation counts for recent articles need time to grow.I introduced the topic of altmetrics, or alternative metrics,and how they could help this faculty member build a morecomplete picture of their research impact.Altmetrics measure research impact by includingreferences outside of traditional scholarly publishing [1].These social web metrics were first proposed in 2010as a response to scholars moving their work online [2].Altmetrics analyze tweets, blogs, presentations, newsarticles, comments, or any social commentary about adiverse group of scholarly activities that are captured onthe web [2].As librarians have been explaining for years, there arelimits to what IF and h-index figures can tell us. A juniorfaculty member may have created and shared hundreds ofcaptivating lectures online but only published a fewarticles. That teaching is not reflected in their h-index.They may author a widely followed blog in which theyengage with an audience of academic peers, but there is noIF for the blog. As numbers of Twitter followers orFacebook friends quantify social media activity, altmetricsmeasure and rank researcher output, impact, and influencefrom the social web.Before continuing, I should declare any possible con-flicts of interest. I have been a tester for Altmetric.comsince September 2013, and I have enjoyed free access to theAltmetric.com Explorer. Aside from that association, I ama health librarian working in an academic research centrewithout any financial interest in altmetric products. I amwriting from the perspective of an information specialistwho uses altmetrics to track research publications, toassess the impact of my centre’s social media communica-tion strategy, and to plan future knowledge disseminationprojects.I first heard about altmetrics at the Medical LibraryAssociation conference in 2013. The topic of this intriguingnew cross-section of social media and article metricswas heard at numerous sessions. Altmetric start-ups werepushing products that measured research in a differentway, and librarians were excited to learn more.The obvious caveat about altmetrics is that they are onlyvalid and valuable for the most recent publications [3, 4].A 2013 publication in Annals of Internal Medicine on lifestyleinterventions for diabetes [5] received a score of 148 by theAltmetric.com Explorer. The score was calculated basedon 128 Twitter users sharing the publication, two bloggersciting the article, and seven Facebook users mentioning it.In context, the article was amongst the highest ever scoredin Annals of Internal Medicine, (ranked 37 out of 2470). Incontrast, a 2005 publication from the same journal oncoronary artery disease [6] received no score. Social mediamentions are rare for articles published prior to 2011 [4, 7],and altmetric products often exclude older datasets in theiranalysis [8].Some altmetric tools, such as Altmetric.com in theaforementioned example, tell us about individual articlesand others tell us about researchers. Researcher-focusedproducts, such as ImpactStory and ResearchGate, resem-ble familiar social networking sites in that they rely oncontributors creating and maintaining personal profiles.The evolution from Facebook to LinkedIn to ImpactStorymakes logical sense. User-contributed profiles becameonline re´sume´s and then dynamic curricula vitae withembedded metrics for research products. For researcher-focused altmetric tools, older publications, presentations,and products can be manually added. These products thattell us about researchers are more likely to includecontributions prior to 2011, and for that reason they arebetter for analyzing research output over time than article-focused altmetric tools.Because different altmetric tools tell different stories, thelandscape is full of start-ups positioning themselves as