Oh internet, never change. I managed to get into a fun argument on whether smileys count as sentence-terminating punctuation or not. That is, which of the following sentences is correct:
I like dogs : )
I like dogs. : )
edit: spaces added to prevent wordpress from emojifying them, which I find incredibly annoying
Clearly, smileys (not to be confused with emoji) are absolutely self-sufficient sentence-terminating punctuation, both in a fairly literal sense (they’re mostly *made* of punctuation) and in a practical one. Terminating punctuation serves to visually separate sentences and additionally sometimes to indicate intent (periods are neutral, but question marks, exclamation points, etc. carry additional content). In exactly this fashion, smileys visually separate sentences while simultaneously indicating a whole range of emotional content.
When a period is immediately followed by a smiley, it becomes redundant; it is no longer needed as a separator, and the smiley’s emotional content trumps the period’s neutral aspect.
When an exclamation mark is immediately followed by a smiley, it serves only as additional emphasis which is usually better expressed through the use of a more extreme smiley such as “:D” in place of “:)”.
When a question mark is immediately followed by a smiley, it’s just confusing. The question mark already indicates a basic quizzicality and any other emotional content carried in the smiley risks contradicting that.
That covers all the standard terminating punctuation marks used in English. It should now be clear that smileys count as terminating punctuation in their own right, and that anybody who thinks differently is simply wrong 😉