This functionality is attached to the "unwatchedpages" user right. By default, only administrators have this user right. However, it's perfectly possibly to add a custom user group with this user right.

On which wiki would you like to be able to see the number of page watchers?

(In reply to comment #1)

This functionality is attached to the "unwatchedpages" user right. By
default,
only administrators have this user right. However, it's perfectly possibly to
add a custom user group with this user right.

On which wiki would you like to be able to see the number of page watchers?

You means that If the user have the "unwatchedpages" user right,he can watch
the watchers' count of the page at the page of page information which the watcher of the page lower 30 people but more than 0,is it? I thought that the "unwatchedpages" user right can make the user watch the page which none wachted at the special page.

And I hope this functionality can be the part of mediawiki software.Not just at some wikiproject.

(In reply to comment #2)

You means that If the user have the "unwatchedpages" user right,he can watch
the watchers' count of the page at the page of page information which the
watcher of the page lower 30 people but more than 0,is it?

Yes: bug 39957.

So this turns out to be a wording issue, causing the original reporter's misunderstanding of this user right.

Maybe I don't want to change the definition of "unwatchedpages" because I don't want that the user who not the administrator can see the Special:Unwatchedpages page.Just the user with a right or right group can see the count of page watched by between 1 and $wgUnwatchedPageThreshold at the action of page info.Maybe the user right group is a good resolution,but because this's just my idea without any common consensus yet,I don't sure that it's good enough to add a new user group and anyone think that it's helpful.

(In reply to comment #5)

Maybe I don't want to change the definition of "unwatchedpages" because I
don't
want that the user who not the administrator can see the
Special:Unwatchedpages
page.Just the user with a right or right group can see the count of page
watched by between 1 and $wgUnwatchedPageThreshold at the action of page
info.Maybe the user right group is a good resolution,but because this's just
my
idea without any common consensus yet,I don't sure that it's good enough to
add
a new user group and anyone think that it's helpful.

It doesn't make sense. In your design ordinary users can iterate over action=info of all pages, and write down the title of every page they see which has no watcher, to compose their own Special:UnwatchedPages.

(In reply to comment #6)

(In reply to comment #5)

Maybe I don't want to change the definition of "unwatchedpages" because I
don't
want that the user who not the administrator can see the
Special:Unwatchedpages
page.Just the user with a right or right group can see the count of page
watched by between 1 and $wgUnwatchedPageThreshold at the action of page
info.Maybe the user right group is a good resolution,but because this's just
my
idea without any common consensus yet,I don't sure that it's good enough to
add
a new user group and anyone think that it's helpful.

It doesn't make sense. In your design ordinary users can iterate over
action=info of all pages, and write down the title of every page they see
which
has no watcher, to compose their own Special:UnwatchedPages.

I see.I think MZMcBride's design is nice.But I'm not sure that add a new user group with "unwatchedpages" right is good or helpful because I don't know how many user who not the administrator need to watch the count of the page less 30 watchers.Would it make the administrator confused?