Imagine you and someone from Thailand are chatting somewhere and sometime on the Internet. Imagine that, in the course of the conversation, you, and this may require some extra imagination say something utterly, awesomely hilarious.
Out of nowhere, you see your new friend just sent you “55555”. You ignore it, then you say something funny again and you get another “55555”.
What it’s all this about? In Thai, the number 5 is pronounced "ha" so instead of saying "hahahahaha," Thai speakers will sometimes write "55555."
In another words, you should feel happy for making your new friend giggle! If you’d like to use a new shortcut for “HA” now you know that “5” can be used for the same purpose.