It is very dependent on how you treat and use the software. Most forum platforms would be fine, as long as you use the security features e.g. CAPTCHA. The main thing is that you find the modifications present to combat spam. They are very useful.
Mybb since it's under the radar of most spammers. Stuff like Xrumer target VB, phpbb, IPB, and SMF for the most part. There aren't enough mybb site for them to bother targetting. Mybb also comes with Akismet plugin on download. This will greatly reduce any automatted or even manual spam that does come across your site.
i been using phpbb-seo with two CAPTCHA mods, and it stop a 100% of all spam, and about 30% of real user who are too stupid work out the use CAPTCHA.
vbulletin is also a victim of spam. i suppose you have to install certain mods and ban users. i think akismet for vbulletin is commercial.
Nope, I don't think so. You just have to sign up for a WordPress account to get the Akismet Id thingy and then you can use it.
The term "spam" is too broad. Do you want to keep out spam bots? Do you want to keep real people that post spam from signing up? As for keeping real life people, that post spam messages from signing up - its impossible. Its goes against what a forum is all about. Sooner or later you will get some kind of spam post, even if its by a real person with a real email address that they confirmed when they registered. For spam bots, a good capthca will do. My VBulletin forum has been online for about a year and a half. I use captcha, and one more required question when the person registers. And guess what, I do not have a problem with spam. I dont even make members confirm their email address. The people that I see with a spam problem are those that turn captcha off. And then complain that they have a spam problem. The big players in forum software are good at dealing with spam bots, its "how" the administrator uses those tools. Regardless of what forum software I recommend, if you do not know how to use that software - its not going to do you any good.
i have got the same problems on my forums.. there are alot of Spamers and i m sick of banning them...
No scripts will block spam out of the box, most software's will have anti-spam mods that you can add. if your using vb, check out the nospam or search "spam" at vb.org you'll find several spam mods
Mybb has Akismet in base package. You just activate and add your key. It's ready to use out of the box.
You could install an advanced captcha box, or a mod to add a anti spam question on registeration. This would stop scripts registering just to spam