We just detected a whole network of spamming/abusing bots who use Tor exit nodes to sign up for fake trial accounts - in Saas apps that have some inbound/outbound email functionality (like webmail services, helpdesk apps, email marketing apps etc.)
I’m talking tens of thousands of fake user accounts and trials.
Anyways… Long story short you might want to block Tor exit nodes from accessing your website or at least your landing pages/signup forms. At best they will ruin your metrics. There’are no paying customers there anyway.
If you’re using a CDN - it probably has a a built-in way to do this. If not - you can quickly detect a tor-node IP by running a special DNS query, just google for examples in php/ruby/whatever.
PS. their intent is still unclear to me, seems like they’re building a massive network of fake email addresses, probably used for fake social profiles used n click-fraud. Just my guess…