Is there a way to fake users browing a specific category?
 

I mean not the forum stats but a specific subforum like showing (100 users viewing).

I dont want to use it because my forum is growing but Ive seen some forums who have 240 users viewing a subforum but none of them post or even commnet. It is a dead forum

Are you sure it is not spiders viewing that page?

I dont know , maybe they created them or it is a plugin o vb

and why people use them

I do not recall seeing such a mod, I would have to believe it is spiders viewing it. IMO it would be silly to show 100 users viewing a thread, and only 3 people logged into the forum forum stats. :)

It's not unusual to see dozens of spiders on a specific topic or even a subforum. Baidu is particularly prone to do that.

maybe, but sometimes they have 300 spiders :O

Here is the current stats from this site:
Currently Active Users: 648 (44 members and 604 guests)

Here is what is viewing vB4 mods:

vBulletin 4.x Add-ons (136 Viewing)

As you can see the numbers can become inflated easily.

Baidu is a particularly nasty crawler that ignores robots.txt and is known to bombard forums with hundreds of hits at a time.

That's why alot of people block it, using Simon Lloyd's "Ban Spiders by User Agent" mod.

Thats one of your settings in admincp, the viewers are not separated so the 100 will be made up of bots/spiders and real users and they dont have to be logged in for that stat to show them viewing, i think it's with the option to show who's viewing a forum.

You can change it in phrases $vbphrase[x_viewing] or change it in:
forumhome_forumbit_level1_post and remove
<if condition="$show['browsers']"><span class="smallfont">(<phrase 1="$forum[browsers]">$vbphrase[x_viewing]</phrase>)</span></if>
And the same in forumhome_forumbit_level2_post.

There are mods that fake online users, but they fake...online users. Not just the view count without any usernames. The number of spiders on a site can be ridiculously, needlessly high. Which is why you sometimes have to ban them.