I suggest to make integral a synonym of integration.
integral $\times 25$, no usage guidance
integration $\times 717$, has usage guidance.
I can see no distinction between their use, I think these are practically strict synonyms.
This question has generated a lot of discussion while I was looking away! Here are my thoughts.
The primary purpose of tags is to aid with search. As mathematicians, we have a tendency to think in terms of classification and taxonomy instead, but this is not the best way to think of tags and we should make an effort to stay away from this kind of thinking.
continuity seems to have no coherent use. It has 3 watchers for 88 questions, which is a very low ratio (compared to tags with a comparable number of questions).
It's mostly to mean some use of continuity, often somewhere fitting with real-analysis, gn.general-topology, and others. This number of questions is ridiculously small compared to the number of ...