On the popularity of reference managers, and their rise and fall
This weekend, I had some spare time and I wondered which was the most popular reference manager (and how Docear is doing in comparison). So, I took a list of reference managers from Wikipedia, and checked some statistics on Alexa, Google Trends, and Google Keyword Planner. Since I had the data anyway, I thought I share it with you :-). Please note that this is a quick and dirty analysis. I cannot guarantee that there is not one or two reference managers missing (i just took the list from Wikipedia), and, of course, there are many alternatives to Alexa and Google for measuring the popularity of a reference manager.
Google Trends shows a picture most people would probably expect. Endnote, Zotero, and Mendeley are the most popular tools, i.e. they accumulate the highest search volume. It should be kept in mind that the true popularity of “Endnote” probably is a little bit lower, because some people searching for “Endote” might not be interested in the reference manager but in some information about endnotes in general. What is quite interesting is the high search volume for “NoodleTools”. To be honest, I wasn’t really aware of NoodleTools. While you permanently stumble upon Zotero, Endnote etc. when looking for reference managers, NoodleTools seems to be widely ignored by most reviews. Also Docear’s users typically use(d) e.g. Mendeley or Zotero but hardly anyone ever used NoodleTools before.
When using Google Keyword Planner, NoodleTools even has the highest search volume, followed by Endnote, Zotero, and Mendeley (don’t ask why Google Trends and Keyword Planner report different search volumes – I don’t know).
Alexa measures the number of visitors a website has and shows a different picture of the reference managers’ popularity than Google’s search volume. Bibsonomy and CiteULike rank first and second respectively, and the (discontinued) Connotea also ranks quite high (#5). Of course, these reference managers are all web-based. This means, users of e.g. Bibsonomy visit bibsonomy.org each time they use the tool. In contrast, users of e.g. Docear usually visit docear.org to download the software or get some support. Plausibly, traffic statistics of the web-based tools are higher. However, I find these numbers still surprising because they are so massively high for e.g. Bibsonomy, although the search volume is rather low. It’s also interesting to note that EndNote ranks only #7 while it ranked quite high according to search volume. RefBase, RefWorks, JabRef, Referencer, etc. have a ranking of 0 because Alexa did not provide any (reliable) data for them. The reason is that these tools don’t have their own domain but are hosted e.g. on Sourceforge, and Alexa only returns traffic statistics for the main domain, i.e. sourceforge.org instead of e.g. jabref.sourceforge.net.
On average, Zotero is the most popular reference manager, followed by EndNote and Mendeley (I just calculated the mean of the previous three rankings). Also popular are NoodleTools, RefWorks, and CiteULike. What makes me personally quite happy is the good ranking of Docear :-). According to all three ranking methods, Docear ranks #9 or even #8. I think that’s not bad given the rather small development team of Docear, and considering how young Docear is :-).
The above picture shows all three rankings in a single chart for an overall overview. The following pictures are all retrieved from Google Trends. They illustrate the fall and rise of some reference managers.
The search volume for Endnote continuously decreases. All other top-ranked tools rather gain popularity, although it seems that Zotero and Mendeley are “saturated”, according to search volume (of course, when the search volume remains constantly high, the tools still gain a remarkable number of new users every month). A little bit surprising is the high variation in the search volume for Noodletools and also RefWorks. I have no idea how this could be.
The search volume for Citavi slowly, but constantly, increased over the past years. In contrast, JabRef, Referencer, and CiteULike quite significantly lost popularity.
The above picture shows even clearer how the interest in CiteULike decreases. While CiteULike once was far more popular than Docear, search volume for CiteULike and Docear is nowadays about the same. Bibsonomy and Colwiz have a comparable search volume (about half of Docear or CiteULike). However, for Colwiz the search volume remains constant over the years while for Bibsonomy it is decreasing.
It seems that around 2005, Biblioscape was quite popular but nowadays it’s hardly searched for any more. The search volume for Connotea is also constantly decreasing since its launch in 2005. So the consequence of the Connotea team to discontinue their service was probably quite rational. KBibTeX and Pybliographer’s search volume is close to zero (see chart above). Search volume for the remaining reference managers (WizFolie, RefBase, Wikindx, SciRef) is also close to zero (see chart below).
To give you an idea, about what dimensions we are talking …
… this is the search volume for Facebook and Linkedin, and…
… this is the search volume for LinkedIn and Endnote. What does this mean? It means that the demand for reference managers is far far away from the demand of popular websites like Linkedin or even Facebook. Of course, the demand for reference managers will never become as high as for a social network such as Facebook. However, I believe that some day the demand becomes at least close to the demand for e.g. a professional network like Linkedin. From personal experience I know that there are many students and researchers who don’t use any reference manager at all (yes, they really do all the work manually, including formatting references e.g. in MS Word). So, there is still a lot of potential for the search volume to go up. To be more precise, based on Mendeley’s claim of having around 2.5 million users, we may estimate that there are around 10 or 15 million people who use reference managers overall (of course, this is a very rough estimate). Since there are about 100 Million students and researchers in the world, there are still some dozens of Millions to convince from the benefits of Docear & Co :-).