Sorry it has taken me so long to reply! I wanted to revamp our online documentation, and then it slipped through the cracks.
So, here are a few links that I think explain how we compare to Altmetric, CED or Plum:
What is Cobaltmetrics?, which now includes short blurbs re: citation indices, altmetrics aggregators, and backlink databases;
- Our URI transmutation API, which I think surpasses their search engines when it comes to aggregating/deduplicating results.
In terms of data sources, we have no interest in indexing Twitter, Facebook, or Reddit all over again. We do index some sources that are available elsewhere, e.g. Wikipedia, to show that we’ve done our homework—and to pave the way for benchmarks—but our goal is to leave behind social media and go web-scale to explore new data sources.
We’re currently working on ingesting CommonCrawl data, which isn’t trivial giving our resources. (We’re also interested in “altmetric archeology” and sources like Usenet or Gopher if you’re into that kind of stuff.)
In the long run, we want to build something that complements the limited offer for altmetrics data, rather than merely competing with existing players.
I hope this helps, please let me know if I can help in any way!