Multiple domain, 1 database possible?
 

domainA.com -> forum a b c d e
domainB.com -> forum e

one database for all
but i want forum e got their own seo, i mean
when it comes to forum e then domainB.com/seo-blabla/ not domainA.com/seo-blabla
is this possible?

There's a mod called 'different domain, different style' which lets you use different sets of templates depending on which domain the user is coming in on. You could then use conditional statements in those templates to only show certain forums. You may or may not need multiple vbulletin licenses for this.

While this mod doesn't share the same db install, it will show forums from Site A on Sites B, C and D. You can use HTTAccess files to block spiders and avoid duplicate content issues.

vbNetwork - share forums with other boards


The only issue with this mod, is that it doesnt sync the user tables between the sites but im sure you could do that via alternate methods.

We need to resurrect this.
I have seen this request appear a number of times, and I've even had clients request that this be done a number of times.

You will need to consider the licensing, however. Whilst you're using the one installation of a board, you're theoretically running multiple forums. That would mean you need multiple licenses, apparently.