One of the most popular technical Questions and Answers (Q&A) websites is nowadays represented by Stack Overflow. Compared to a more traditional mailing list, it provides different advantages:
- More structured information
- Focus on the problem/issue
- Information easier to find
- Threads easier to follow
- Concept of reputation (most active users “rewarded”)
- Up/Down votes
- Etc.
I’m not suggesting that Stack Overflow should exclusively replace every existing mailing list. I rather feel that the two tools may coexist, with different purposes.
- Technical problem/issue -> Stack Overflow
- Open discussion -> Mailing list
Recently, I’ve noticed an increased number of posts tagged Erlang on Stack Overflow. I then asked myself:
- How Erlang is growing on Stack Overflow?
- How the Stack Overflow growth is affecting the Erlang mailing list?
- How Erlang is growing on Stack Overflow in relation to the major (read, most popular) languages (such as C++, Java or PHP)?
- How Erlang is growing on Stack Overflow in relation to languages such as Scala, Haskell or Go?
Then, I’ve tried to give ananswer to all of these questions.
How Erlang is growing on Stack Overflow?
Probably you don’t know, but there is a website (odata.stackexchange.com), which allows you to run arbitrary SQL queries on the Stack Exchange family of sites, of which Stack Overflow is part. Well, I decided to write my first query, asking Stack Overflow about the trend of posts tagged Erlang over time. The query is parametrical and can be used to check the trend of any tag on Stack Overflow. Also, since my SQL Server skills honestly suck, you are very welcome to edit and to make more efficient my query.
The charted results of the query run for the Erlang tag look more or less like this:
Where the x-axis ranges from August 2008 to October 2010.
How the Stack Overflow growth is affecting the Erlang mailing list?
Gmane offers a whole set services related to mailing lists. Among these, it provides some really interesting statistics on the mailing list usage. The following graphs report the messages and the participants per day for the Erlang General mailing list for the past few years. You can find more details here.
To a very first analysis, it seems that the recent growth of Stack Overflow didn’t affect too much the Erlang mailing list, even if you can notice a tiny decrease in the mailing list usage in the final section of the graph (period 2008/2009). It sounds obvious how Stack Overflow shouldn’t be seen as the unique possible affecter of the mailing list usage.
How Erlang is growing on Stack Overflow in relation to the major (read, most popular) languages (such as C++, Java or PHP)?
A graph is worth a billion words.
How Erlang is growing on Stack Overflow in relation to languages such as Scala or Haskell?
Conclusions
Comparing Erlang with the major languages such as PHP, C++ or Java is probably a bit unfair. I just hope you enjoyed reading this simple case study as much as I enjoyed writing it. Feel free to play with my query. Comments and opinions are always welcome.




Hi Roberto,
your analysis is interesting, and it indeed shows that the usage of Erlang is growing.
We all know the advantages of SO w.r.t. a mailing list, among the others the latter forces you to register and, in some way, to “engage” with the project, while SO has less barriers.
Regarding the analysis itself, I believe that you should normalize your data with the total number of posts in StackOverflow for each months, or in some other way. The increasing trend shown by your graphs may be largely affected by the increase of the popularity of StackOverflow itself!
Posted by Andrea Spadaccini | December 13, 2010, 1:36 pm