Should emoticons be regarded as punctuation marks?

According to Wikipedia, “[p]unctuation marks are symbols that indicate the structure and organization of written language, as well as intonation and pauses to be observed when reading aloud”.

Does this make emoticons – when used along with a sentence, e.g., “I am good :)” – eligible to be considered as punctuation marks? They seem to satisfy the “intonation” criterion.

Apparently, there's as yet no canonical rule about emoticons.

As no one seems to have officially declared them as marks of punctuation or members of the class, emoticons cannot presently be treated as punctuation marks. Even where they incidentally appear to serve to punctuate a sentence, maybe.

The jury is still out on that one.

A brief mention of interest: Emoticons as Punctuation Marks

Punctuation:

a mark, such as a full stop, comma, or question mark, used in writing to separate sentences and their elements and to clarify meaning.

Emoticon:

a representation of a facial expression such as a smile or frown, formed by various combinations of keyboard characters and used in electronic communications to convey the writer’s feelings or intended tone

So, no, emoticons are not punctuation, because they are not used "to separate sentences and their elements".