I did not know which topic to post this so, I am posting it here. I have been Postcrossing for 4 years (300 cards). I love it! I am usually a quiet guy, but in postcards I put some of me. I tend to write small on the cards in order to flood it with content. I like getting these types of cards.
Anyway, I had an I idea. I thought of starting to send a monthly email/electronic postcard. I have an iPhone and was thrilled to find an app that lets you create a card with your picture, title, message, and even stamp. I like it because it actually places a canceled stamp with the date, and place you sent the picture. (see example). The app is called Postale.
I did not want to give my personal email out, so I created an email account just for this purpose ( postcrossing22@yahoo.com ). If you send me an email message to my email. I will send you 1 or monthly “postcard”. Regards. -Gmansocal
You are free to do so, but I think it misses the magic of a real postcard with marks and dents after the travel. And it also misses the magic of a surprise, for you need to ask the receiver for his e-mail-address. And, of course, it cannot be an official Postcrossing card, for not travelling physically.
But, if you find people willing to exchange electronic postcards, have fun!
Or possibly this would be a good topic for a Tag?
I applaud your thinking outside the (mail)box!
So, I think that’s not the point of postcrossing.
For me it is the tension to open the mailbox and see if I got another postcard. From an unknown person. If I already know in advance that I will get a card - then the fun is no longer there.
In addition, but that’s my personal thinking, I don’t want my email address to be distributed all over the world. So this is generally not for me.
But if you find people who are willing to participate - then I wish you a lot of fun!
I thank all who wrote a response to this post. I agree that getting a postcard, especially one which is unexpected is exciting. I did not mean in any way we should stop sending postcards. I just thought of doing this because I like the way the electronic card looks (again, see sample). Some pictures I take with my phone can tell it’s own story. Regards. -G
I do swaps through another site called Swap-Bot. I think you might find an audience there who is more receptive to this type of online swap. There are swaps there for everything, from teas to postcards to craft materials to online pictures. 
EDIT: I thought I was in my personal account, LOL. This is the account I use for my Assisted Living residents at work to swap postcards around the world. My personal account is AmyMCGS.