In my opinion, vBulletin is by far the best forum software, but it can create some problems for your website.

Most sites work very hard on creating good quality content, but once they add a forum the site will attract a lot of user-generated content and low value pages.

The first thing you need to do is make sure that your directory indexes are set in your htaccess file. This means that yoursite.com/forum will redirect to yoursite.com/forum/index.php, rather than just showing a page with a list of all the files. Make sure you do this for every single directory in your site.

Secondly, you should use robots.txt to remove all the low quality pages. Here is the file you need to use:

User-agent: *Disallow: /forums/archive/Disallow: /forums/admincp/Disallow: /forums/attachments/Disallow: /forums/calendar.phpDisallow: /forums/clientscript/Disallow: /forums/cpstyles/Disallow: /forums/customavatars/Disallow: /forums/customprofilepics/Disallow: /forums/faq.phpDisallow: /forums/images/Disallow: /forums/install/Disallow: /forums/includes/Disallow: /forums/login.phpDisallow: /forums/misc.phpDisallow: /forums/member.phpDisallow: /forums/modcp/Disallow: /forums/memberlist.phpDisallow: /forums/newreply.phpDisallow: /forums/newthread.phpDisallow: /forums/private.phpDisallow: /forums/register.phpDisallow: /forums/sendmessage.phpDisallow: /forums/signaturepics/Disallow: /forums/sendpm.phpDisallow: /forums/search.php

Each website will only have enough trust to get a certain amount of pages indexed. Don't fill the index with low quality pages.

Some people might want to index members profiles; that's fine. I just chose not to at the moment.

To remove any pages already indexed, simply upload the robots.txt and visit the strangely hard to find and almost mythical Google Console.

If you have any questions on how to implement these changes, please post in the comments.