As Jason Priem and Heather Piwowar of Impact Story noted, altmetrics need to be “accurate, auditable, and meaningful” to everyone who relies on them. If a service counts tweets, then it should not only do so accurately, but I should be able to see the tweets that have been counted; if it counts annotations, then I should be able to know that it has discarded spam and trolls, and that I can peruse the annotations included. Todd Carpenter of NISO suggested that useful numbers might be certifiable, in the same manner as in the advertising industry. - http://blogs.publishersweekly.com/blogs/PWxyz/2013/10/15/measuring-altmetrics/