Because of a drastic increase in spam emails over the past month, I am re-enabling email greylisting. Greylisting is a great technology that requires mail servers to automatically resend messages (spammers generally can’t leave servers running to do this, for risk of being caught and prosecuted). This will only happen the first time you email me after I enable the technology, and you probably won’t even know it happened.
For the vast majority of you, this all means absolutely nothing and will have no effect on your ability to email me. However, a select few ISPs and email providers have incorrectly configured their mail servers. People who use those services will receive errors when sending to me. If you get such an error, please let me know via IM (so I can manually whitelist you) and, more importantly, ask your ISP to configure their servers properly so greylisting can be adopted on a wider scale.