Why does the thread on resource in the moon have a link to a webpage under the thread title?

[cochrane]

Here’s the thread in question:

Resources on the moon and Mars

Inspired by a discussion here, I got to thinking: what resource (I assume a mineral) could realistically be discovered on the moon that would make extraction and delivery to Earth financially viable? In what quantities? And what would need to be found on Mars to make the trip back to Earth lucrative enough to justify it?

Where the tag usually goes, there is a link instead, above the body of the OP.