I'm Ryan, one of three devs that built FraudGuard.io. Honestly we have a lot more work to do specifically in spam. With that being said, spam is the least requested collector so far by our users. Just to share in beta we asked some of our heavy users and about 90% of our users preferred our focus was on honeypot collection, spam was less than 2%.

So heres how it works now. We do not rely on external sources at this time. The reason why, because our traffic is so high that no external source at least that we've found will serve our users traffic.

For example stopforumspam.com limits API requests to 20,000 per day. I haven't checked our stats today but during our beta (which ended yesterday) we served more than 20,000 API requests per hour. So even with huge cache durations set its very hard to rely on outside sources so instead we run all our own spam collectors, using our own domains, etc.