Some blogging software "helpfully" changes double hyphens to en-dashes, triple hyphens to em-dashes, and triple dots to ellipsis characters, which garbles Morse code. So I use E and T instead.
The message was inspired by a little deciphering adventure I had yesterday on the Rifftrax blog when Bill Corbett posted a message in Morse code. I tried to decipher it by copy-pasting it into Notepad and doing search-and-replace, but I ran into trouble, which I soon discovered was caused by the blog software's reformatting, as described in my message above.
At the same time, it occurred to me that there are two possible ways to decipher Morse code by doing search-and-replace. One is to start with the longest dot-dash sequences, the ones of six characters that form the punctuation marks, and then decode all the five-character strings, then the four-character strings, etc. This is the common-sense way to do it, because if you start at the short end of the scale, longer strings will be altered by shorter replaces.
But then it occurred to me that this didn't matter; starting at the short end would work too, it would just be weirder. First, change all dots to 'e' and all dashes to 't'. Then do 'et' -> 'a', 'ee' -> 'i', 'tt' -> 'm', and 'te' -> n. Then more weird letter combinations will start to show up, but it's easy enough to figure out what letters they're supposed to be. For instance, 'ti' = - .. -> -.. -> 'd'.
And then it hit me that if you only did the first step, using 'e' for . and 't' for -, you could post that on any blog without it being mangled by any fancy-punctuation-substitutin' code.
Then I wondered, if I posted a message like that, how many of my friends would figure it out and decode it? :}