Sure the MMM quiz thing is still active, but this site is likely high enough for the Google Analytics to make it attractive to google the answer for the spammier of posters.
But mostly these are either clueless: oops, I'm not really a spammer, but this is kinda spammy (the "hey, here's my blog" crap) or just desperate DIY folks that stumbled over the MMM forum in a random "how do I fix this" search.
But good ways to recognize really stupid spammers:
First posts from folks that start talking about random shit that really has nothing to do with the forum, and post a link to something they're "considering" purchasing or have recently purchased. This is totally spam crap. No one comes into a forum brand spanking new and wants opinions on shit that they just bought from some random site that just happens to sell the shit for a markup over what you could get it just about anywhere else...
First 3-10 posts are "hey that's great" or "I'm following this - super info!" nonsense garbage. Most forums have a lockdown on the ability to add pics/links until a poster has a few posts first... so they do this shit to get their post count up and then start spamming. Unfortunately, this forum lets you post pics or links from the first post so we get LOTS of spam here.
Low post count poster (spammer) that bumps an ancient post from a year or more because they needed to add their spam link - folks on here in general are terrible about looking at the dates on posts. I've seen spammers bump threads that are 3-5 years old... and then regular members pile in to give their opinion on the subject even tho the spammer's post was deleted and the OP of the thread likely is either gone for years or got their answers from the first round back when the thread was relevant. This is a personal pet peeve of mine, because usually it's good forum hygiene to remove any of the new posts after you remove the spam that bumped it that would keep that necro thread from dropping back into its grave, but they don't tend to remove the newer posts from those members that didn't pay attention to the age of the thread. :(
The mods are doing a great job, but flag any shit posting that looks spammy if you see it because there is just so much they can do on here themselves. They can decide if it warrants removing - but at least it's a way to help keep the forum clean of spammy crap. When in doubt, alert the mods and let them decide.