I know how to filter spam from email (to trash directly, without flagging scirra as spammer) but those who don't - getting over 400 messages per day might be annoying.
Without filtering situation would be; Gmail nicely categorizes same subjects "Scirra (40)" so I won't see 40 mails directly from that but when spammer has different username - different collection of emails gets piled and mobile device beeps several times per hour.
I just hope that SNS won't cause problems in the future for Scirra.
Adding some custom checks has helped when I did run forums. "What is the name of the product we sell", "check only third and fifth checkbox to prove you are not robot", "leave this field empty". It causes too much customization to spamming scripts them to deal it.
Also adding delay when new users can post (like an hour) has cut many "hit and run" spammers.