My email address is Bjorn@Rombobjörn.se. If your email program thinks that address is invalid, you can use Bjorn@Rombobeorn.se instead. Don't miss the conditions below.
The world is full of snoopers who want to ransack other people's private correspondence and chart who corresponds with whom. They may be anything from multinational spy combines to prying neighbours and total strangers across the world. In order to keep at least the contents of the messages private I ask you to encrypt them. For that you need Gnu Privacy Guard (GnuPG), Pretty Good Privacy (PGP) or some other program that complies with the OpenPGP standard. You also need my PGP key to encrypt with. It's also good if the encryption can be handled in the email program, so that encrypting won't be a nuisance. For many popular email programs there are plugins available to integrate them with GnuPG or PGP.
Keep in mind that OpenPGP encryption protects only the contents of the message. The message header is not encrypted, so the sender and recipient addresses and the subject line are not protected against espionage. In the OpenPGP/MIME format the text and any attachments are encrypted. In the legacy PGP format only the text is encrypted, not the attachments.
Encryption is also useful for making sure that your messages will reach me, but it's not mandatory. You can reach me by unencrypted email too. This brings us to the next point:
Spammers are undoubtedly the most abominable scum ever to besmirch this planet. To keep them out of my inbox I've been forced to set up some special conditions for people who want to send email to me. To make sure that your message won't be rejected, take at least one of these measures:
Furthermore, all messages shall be correctly formed in accordance with the standards for email. You won't normally need to worry about this if you have a reasonably sane email program, but if your messages are rejected despite meeting at least one of the requirements above, then a defect in your email program may be the cause. That should then be clear from the error message in the bounce message you get.
Why do I complicate the matter in this way? Why don't I use a spam filter like everyone else?
Spam filters cause a continual arms race. The filter developers try to make the filters smarter, while the spammers try to fool or sabotage the filters and also send out more and more spam so that the small fraction that slips through the filter still becomes an unacceptably large amount. All spam filters also sometimes err in the other direction, so that they discard some fraction of the legitimate messages, and they typically don't inform the sender when they discard a message. The only way to defeat the spammers is to do something about the root cause, which is that sending email to stangers is too easy and too cheap. This is what I do with my conditions. A real human being can meet the conditions without too much effort. Many people won't even notice them. To a spammer, on the other hand, it will be too troublesome to meet the conditions just to reach one more victim.
The advantage to you as a sender is that you have the means to ensure that your message will reach me instead of just hoping that it won't get eaten by a capricious spam filter. My server accepts all messages that meet the conditions, and those that it doesn't accept, it rejects with an error message. If a rejected message wasn't spam but a legitimate message, then the rejection will result in a bounce message to the sender with the error message in it. The sender will therefore know that the message was rejected, and can take one of the measures above. (I can of course not guarantee that messages won't disappear before they reach my server, or that bounce messages won't disappear on the way back, as there may be filters somewhere else along the way.)