This question already has an answer here:

The Linked sidebar showing linked-to posts only shows links within the same site. Often, for example on Cross Validated there are links to posts on Math SE or MathOverflow (or other sites) but these are not shown in the Linked sidebar. Why? Such linking would increase the utility of that sidebar.

I am sure the same applies to many other closely related sites.

marked as duplicate by αλεχολυτ, ben is uǝq backwards, Nathan Tuggy, rene, Glorfindel Apr 29 '17 at 18:08

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • @alexolut I'd say it's an exact dupe but I can't vote to close. – caird coinheringaahing Apr 29 '17 at 17:36