Recently, I started exploring the field of scientometrics. There is also an associated journal to get a good grasp of related work.
Excited to discover a great number of online tools to do all sorts of data extractions and analyses:
ScienceScape & Table 2 Net
Gephi (my favourite for data visualisation)
The more I explore this field, the more I can see Elsevier Scopus' usefulness for a scientometric analysis of published scientific literature. Compared to other choices out there, full citation information can be extracted (including the much needed keywords).
There are some other tools (not necessarily for scientometrics) available for working with (collecting and visualising) social media data. Worth checking out:
URL Extractor Tool
InteractiveVis Custom Builder