MyBB Community Forums

OK so here goes: I am running a standardish mybb forum, been doing that for a nnumber of years now and over time we have tried to add additional areas not really suited to forums.

Now we have decided to move the forum to mysite/forum (example) and make the site more. We want to add different areas that arent dependant on a forum system so for example, a buy and sell section, a blog, a news area, maybe a shop (probable not really but you never know)

I think I can do it with wordpress but im curious about other options. Im also unsure if the mainpage will be one of the above ideas or just a splashscreen where you select your options via tabs maybe.

Also, Ideally I want all site users to use the same username so they can post in the forum, make an ad, etc with the same username

as you thought, wordpress happens to be most obvious choice as single sign on might be possible
[however you may have to use a premium bridge system (eg.)]

other choice can be Joomla (you may have to hire an expert to make bridge system) ..

A CMS System covers many aspects, one of those are obviously Forums, hence you can call MyBB as CMS as well, though focused, it doesn't cover e-commerce or blogging out of the box.

When WordPress first introduced it was a blogging engine. Over time as it gained popularity it has moved towards a more complete CMS. You can create custom pages with ease in WordPress.

WordPress also doesn't come with e-commerce or forums integrated, but you can achieve those features by activating plugins (WooCommerce, BBPress).
Similarly MyBB has also provides capability to extend its features through plugins. There are Shop System, Blog System, Subscription System plugins available. The only feature which you can point is making custom pages that is super easy with WordPress, but let me tell you - its not impossible for MyBB, infact very little effort is needed. See here:
https://docs.mybb.com/1.8/development/pl...-new-page/

So, its all possible depends on how your requirement is and how you can handle it.
MyBB is a Forum software, Wordpress is a Blogging platform (formerly). There is no point deflecting focus. 'Extend' feature is there to handle advanced and specific needs. You can extend upto any level either by plugins or with separate (even custom) system based on MyBB's solid platform.

ok so I have installed wordpress on a test site and started customising it. For the moment IM not worried about login being shared alltough I have found a plugin that does it apparantly

Next up, is it possible for mybb to use the main wordpress site theme instead of its own?