I was turned onto bitmessage from a tweet and immediately understood the concept.

Take BitCoin's transaction and block transfer system but use it for messaging.

Added advantage is the burden of 'statement of work' should remove attractiveness for spammers.

Installation is definitely not ready for primetime yet, but simple enough by just cutting and pasting the command line commands provided in the install docs

I used the macports install procedure on my mac-mini

After quite some time spent waiting for all the required bits and pieces to be installed, the program started up without any issue.

Very similar to BitCoin, I created an 'address' which is:

BM-2D8iwjp5AxcwGvQGtUiXuGvpnrTMsYRUT2

Now for the testing. Looking forward to receiving your messages!