There are currently two specific sorting tags:
We then have the main tag: sorting (79 questions).
Should we merge the specific ones with the main one? These are only two of many other sorting methods (including existing questions using other methods), plus not all of the above questions include the main tag. This could just be a moderator-only merging as manual retagging may not be practical.
Implementing sorting algorithms is a rite of passage for all true programmers, and we sure get our share of such questions on this site. It would be beneficial to keep a few tags to help users find similar previous questions.
In practice, there are just a few commonly used sorting algorithms that are simple and fast (O(n log n)). In particular, quick-sort is worthy of study. mergesort has the stable property. Heap sort is taken care of by a combination of sorting and heap. Together, those three algorithms constitute a good foundation for a programmer's education.
What prevents a proliferation of tags for each sorting algorithm? Toy-grade sorting algorithms like bubble sort are not interesting enough to merit their own tags, nor should they be used in production-quality code. It seems to make sense that such tags don't exist.
Basically, the current situation seems to work, so I'd rather not disturb it. There's not much benefit to redefining the tag taxonomy for the sake of consistency.
From tags (emphasized by me)
A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.
If I would like to see how other people implemented the mergesort, then I would look at the merge-sort tag. There is a huge difference between a mergesort and a bubble-sort, with regards to skill-level required, speed, code structure, you name it! Now, in what way is merge-sort similar to bubble-sort? They both do the same thing in the end, sure, but there's a big difference in the way that they do it.
I would prefer having both algorithm-specific tags and a more general tag. The algorithm-specific tag wikis could specify that the "sorting" tag should preferably be used as well.
mergesort is a subset of sorting, just like python-2.7 is a subset of python. This doesn't mean that it all should be grouped together under one tag.
If you take a list of sorting algorithms, you will see that it is quite extensive. Merging those two sorting tags now will prevent us from having a ton of different sorting tags later, and instead have one tag that encapsulates them all.
