Altmetrics measure the impact not only of journal articles but a diverse array of online scholarly outputs such as books, book chapters, data sets, computer code, presentation slides, posters, blog posts, digital humanities projects, and websites.
In addition to scholarly impact, altmetrics also measure impact beyond the academy, for example through Wikipedia citations, media mentions, Delicious saves, Tweets, and Facebook posts. This ability to measure public impact is valuable to authors, institutions, and research funders in helping them gauge the real-world impact of their scholarship and the scholarship they support.
Altmetrics are also more immediate than traditional measures of impact like citations that take time to accrue.
Because altmetrics measure impact beyond the journal article, measure more types of impact, and are available right away, they can free scholars to experiment with and receive credit for new types of scholarly products.
Altmetric data can be viewed within Scopus records, as well as with a free booklmarket from Altmetric.com. Additionally, more and more publishers, like Wiley, are adding altmetric data to their articles.
Article-Level Metrics, similar to altmetrics, are an attempt to measure impact at the article level.
They can include traditional measures of impact such as citation counts as well as newer metrics like the number of times an article was downloaded.
A growing number of journals and publishing platforms are making article-level metrics available. For example, article-level metrics are provided for every article published by the Public Library of Science (PLoS). Metrics include total article views and downloads; citation data from Scopus, Web of Science, CrossRef, and Google Scholar; bookmarks in Mendeley and CiteULike; and mentions on blogs, Facebook, and Twitter.