I have become aware of multiple stack exchange sites where the Mathematica tag may be found. I have only been following it on StackOverflow however, where the majority of activity is.
Some sites do not have enough posts to warrant regular attention. For example, Code Review (beta) only has one post tagged mathematica. Nevertheless, I would like to have been aware of this question.
I am requesting a way to view, on one page, questions from multiple StackExchange sites that have the same tag.
Since this feature already exists, I'll use this space to comment on finding it. Across the bottom of each StackExchange site are links to a variety of group, StackOverflow, Superuser, Math, English, etc. It is clear these are all related, and they all bear the StackExchange button at the top, but it was never clear until now that there is a master portal at StackExchange.com that has features such as the one I was requesting. It would be good if this was more evident to new users, IMHO.