What does exclamation point mean in texting?
An exclamation point "in texting" means the same thing it means in any other textual context.
An exclamation point is a form of punctuation that is used to add emphasis or express strong emotion (especially excitement).
The role of the exclamation point does not change based on the given medium (it has the same effect in a book as it does in a text message).
I hope this helps!