Altmetric, a company founded by Euan Adie in 2011, provides a website where one can look up information on references to journal articles published online from other online sources, such as references to an article from Wikipedia articles, tweets, blogs, Facebook, etc., which will provide you with information on how widely cited the online research may be. To easily access the information, you need to install the Altmetric bookmarklet.
To install the Altmetric bookmarklet for the Firefox web browser (tested with Firefox ESR 52.9.0 on OS X), click on View at the top of the Firefox window, select Toolbars, then select Bookmarks Toolbar so that it has a check mark next to it, which will result in the Bookmarks Toolbar being displayed beneath the address field in which you type URLs. At the Bookmarklet for Researchers webpage, you will see a button labeled Altmetric it!, which you can drag onto the Firefox Bookmarks Toolbar. You can then click on the Altmetric it! icon on the toolbar when visiting a page to obtain the Altmetric information for it.
When you click on that icon, you will then see information like the following example for the Nature article The toxic truth about sugar.
If you click on the "Click for more details" link at the bottom of the displayed Altmetric information, you will be taken to an Altmetric page showing more information on online references to the journal article. E.g.:
Public health: The toxic truth about sugar
Overview of attention for article published in Nature, February 2012