I was wondering if I can go ahead and develop this Chris. I was planning to integrate it for lovinity.org nonetheless so I can go ahead and make code for it for Composr in general with your okay.

I honestly doubt it will work well as a spam solution. I suggest taking a sampling of spam you've received, looking at the domains, and seeing if they are covered. My suspicion is you will find that the global spamming 'community' has tens of millions of spam domains, and this database has just some thousands of high profile scams.

According to their website, they have 57 million domains in their database at the moment, with 10 million having poor reputation scores. According to another source, the total number of registered domains as of 2015 is 294 million.

So statistically, WOT has documented about 20% of registered domains.

In that case, you may be right. This may be better as an addon serving to alert users of submitting malicious links to the website... or serving as a check on clicked external links to warn users they're about to go to a poorly reputable website.

Well it's definitely bigger than I thought, but still I think my advice holds - find some actual spam you were exposed to, and see if this would have blocked it.

If I am right, then this feature may be a good idea (but a lower priority) if we could auto-report links when we punish users for spamming to contribute to the services growth (I can imagine a set of checkboxes per link, and if checked that link(s) is reported.

After some additional research and some valid claims made by others of WOT bias and violations of policies, I think this feature would be a bad idea. WOT is crowdsourced, not a professional analysis website. And they have been known to be biased about the data they provide on website ratings.

Closing this, because of:
https://www.pcworld.com/article/3139814/software/web-of-trust-browser-extensions-yanked-after-proving-untrustworthy.html

Yet their website currently is advertising the extension heavily, which will no longer install. They're a zombie, with I think no active staff.