I just read a forum post by a girl who could not understand why someone wasn’t replying to her SMS when she sent him messages saying ‘hi’. To get specific, she was messaging her ex-boyfriend who is now dating another girl and who said that he ‘wanted to stay friends’.

Rule 1 of sending SMS to which you expect a reply: Have a clear purpose for sending the message. Especially if you’re sending it to someone who isn’t under more of a perceived ‘obligation’ to reply, like a boyfriend.

“Hi.”
So…what? Hi? Is that worth wasting mobile phone credit on?

“Hi, do you happen to remember when Casey’s birthday is? Nobody seems to know, it’s pretty urgent! Thx”
That’s more like it.

There must be a reason for you to send them that message. Even if it’s something simple like:

“Hey, I was just thinking about that time we went to that cake shop a few months ago. I want to go there with a friend, do you remember the name?”

Much better than “Hey…I was just thinking about you.”

Of course, messages should be kept rather short due to their size limit, but that’s not an excuse to send crappy messages and then expect the other person to reply. If anything, go over the limit and waste the credit for 2 messages.