In the interest of preventing spam, the function that allows users to send e-mail to other users is now disabled for all users. Users who wish to be able to receive e-mail from other forum members can still enable this function by going to profile in the top menu, then settings, select "Hide your e-mail address but allow e-mail via the forum." and update profile to save the setting.

This function is different from private messages, which are not affected by this change and work just like before.

Has this something to do with a recent event?

Yeah, that's what reminded me of this function. Though, this function could be abused by more "real" spammers which would also not leave much a trace on the server, compared private messages. It's not only that it might be annoying to users to get spam addressed as being by "chipmusic.org mailer", but if such a spam attack happens and a lot of people mark these e-mails as spam, this could also affect other forum e-mail like signup nd thread notifications e-mails.
So I figured it was a good idea to turn it off by default.