I found a temporary solution to prevent spam by private message. (for activated moderation): http://www.question2answer.org/qa/29414/certain-amount-of-points-before-private-messaging File: qa-include/pages/message.php (in 1.7). If you are facing the same problem, enable moderation and add code of Sama55. Thanks.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.