The linked tag on Stack Overflow has no tag wiki, no summary, and is ambiguous as to what it does.
Referring to Jeff's Criteria on Meta-Tags
If the tag can’t work as the only tag on a question, it’s probably a meta-tag
By itself linked doesn't tell me anything useful about the question. A question tagged as Linked would need additional tags to give it any useful context.
If the tag commonly means different things to different people, it’s probably a meta-tag
This is where the biggest issue with this tag is; it is ambiguous as to what "linked" it is referring to. Looking at the tag it is heavily used by questions which refer to linked-list which has its own tag, but has also been used on other questions including linked objects, linking in HTML, LinkedIn, and other uses.
At the moment this tag is ambiguous and subjective in its usage and should either be burninated or synonymized with linked-list and removed from the questions which do not concern linked lists.