I'm going to take a stab at creating some rules for this which - of course - are completely made up and meant to be broken. This is a community wiki: please contribute!

1. If the punctuation is a full-stop, you can replace it completely with an emoji

I went to the cinema today 🎥 The movie was great 😄

This works because people often leave off full-stops in sentences in texting anyway

2. If the punctuation used modifies the sentence (e.g. "!" or "?"), and the sentence ends the line, then the emoji goes after the punctuation:

This is the coolest!!!! 👍👍👍👍

3. But if the sentence doesn't end the line, then the emoji goes inside the punctuation:

This is the coolest 👍👍👍👍!!!!! But it's also not cool 😞

I'm not 100% sure about rules #2 and #3 and would love feedback.

4. Some emoji can replace some punctuation. For example, 🤔 can replace "?":

Do you think it's going to rain tomorrow 🤔

Some of these are more obvious than others:

Wow is that cool❓

Here the question mark is a modifier for the sentence, but in:

Which do you prefer 🐙🌽

The 🐙 and 🌽 emoji are choices and not punctuation, so they count as words. The question mark here is implied.

Other emoji cannot be used to replace punctuation (it's unclear if the "🚫" is answering the question here)

Do you think it's going to rain tomorrow 🚫

5. Emoji used to emphasize through repetition are treated as part of the preceding word:

Do you think 🤔 it's going to rain 🌧 tomorrow?

6. If emoji are part of a quote and are punctuation, they go inside the quote (this is vs some guidelines in English which put the punctuation outside the quote). You can then have another punctuation symbol outside the quote:

"I am very cool 😎", she said.

 

Then he said, "I am also very cool 😎".

I'm going to take a stab at creating some rules for this which - of course - are completely made up and meant to be broken. This is a community wiki: please contribute!

1. If the punctuation is a full-stop, you can replace it completely with an emoji

I went to the cinema today 🎥 The movie was great 😄

This works because people often leave off full-stops in sentences in texting anyway

2. If the punctuation used modifies the sentence (e.g. "!" or "?"), and the sentence ends the line, then the emoji goes after the punctuation:

This is the coolest!!!! 👍👍👍👍

3. But if the sentence doesn't end the line, then the emoji goes inside the punctuation:

This is the coolest 👍👍👍👍!!!!! But it's also not cool 😞

I'm not 100% sure about rules #2 and #3 and would love feedback.

4. Some emoji can replace some punctuation. For example, 🤔 can replace "?":

Do you think it's going to rain tomorrow 🤔

Some of these are more obvious than others:

Wow is that cool❓

Here the question mark is a modifier for the sentence, but in:

Which do you prefer 🐙🌽

The 🐙 and 🌽 emoji are choices and not punctuation, so they count as words. The question mark here is implied.

Other emoji cannot be used to replace punctuation (it's unclear if the "🚫" is answering the question here)

Do you think it's going to rain tomorrow 🚫

5. Emoji used to emphasize through repetition are treated as part of the preceding word:

Do you think 🤔 it's going to rain 🌧 tomorrow?

6. If emoji are part of a quote and are punctuation, they go inside the quote (this is vs some guidelines in English which put the punctuation outside the quote). You can then have another punctuation symbol outside the quote:

"I am very cool 😎", she said.

Then he said, "I am also very cool 😎".

I'm going to take a stab at creating some rules for this which - of course - are completely made up and meant to be broken. This is a community wiki: please contribute!

1. If the punctuation is a full-stop, you can replace it completely with an emoji

I went to the cinema today 🎥 The movie was great 😄

This works because people often leave off full-stops in sentences in texting anyway

2. If the punctuation used modifies the sentence (e.g. "!" or "?"), and the sentence ends the line, then the emoji goes after the punctuation:

This is the coolest!!!! 👍👍👍👍

3. But if the sentence doesn't end the line, then the emoji goes inside the punctuation:

This is the coolest 👍👍👍👍!!!!! But it's also not cool 😞

I'm not 100% sure about rules #2 and #3 and would love feedback.

4. Some emoji can replace some punctuation. For example, 🤔can replace "?":

Do you think it's going to rain tomorrow 🤔

Some of these are more obvious than others:

Wow is that cool❓

Here the question mark is a modifier for the sentence, but in:

Which do you prefer 🐙🌽

The 🐙and 🌽emoji are choices and not punctuation, so they count as words. The question mark here is implied.

Other emoji cannot be used to replace punctuation (it's unclear if the "🚫" is answering the question here)

Do you think it's going to rain tomorrow 🚫

5. Emoji used to emphasize through repetition are treated as part of the preceding word:

Do you think 🤔 it's going to rain 🌧 tomorrow?

6. If emoji are part of a quote and are punctuation, they go inside the quote (this is vs some guidelines in english which put the punctuation outside the quote. You can then have another punctuation symbol outside the quote:

"I am very cool 😎", she said.

Then he said, "I am also very cool 😎".

I'm going to take a stab at creating some rules for this which - of course - are completely made up and meant to be broken. This is a community wiki: please contribute!

1. If the punctuation is a full-stop, you can replace it completely with an emoji

I went to the cinema today 🎥 The movie was great 😄

This works because people often leave off full-stops in sentences in texting anyway

2. If the punctuation used modifies the sentence (e.g. "!" or "?"), and the sentence ends the line, then the emoji goes after the punctuation:

This is the coolest!!!! 👍👍👍👍

3. But if the sentence doesn't end the line, then the emoji goes inside the punctuation:

This is the coolest 👍👍👍👍!!!!! But it's also not cool 😞

I'm not 100% sure about rules #2 and #3 and would love feedback.

4. Some emoji can replace some punctuation. For example, 🤔 can replace "?":

Do you think it's going to rain tomorrow 🤔

Some of these are more obvious than others:

Wow is that cool❓

Here the question mark is a modifier for the sentence, but in:

Which do you prefer 🐙🌽

The 🐙 and 🌽 emoji are choices and not punctuation, so they count as words. The question mark here is implied.

Other emoji cannot be used to replace punctuation (it's unclear if the "🚫" is answering the question here)

Do you think it's going to rain tomorrow 🚫

5. Emoji used to emphasize through repetition are treated as part of the preceding word:

Do you think 🤔 it's going to rain 🌧 tomorrow?

6. If emoji are part of a quote and are punctuation, they go inside the quote (this is vs some guidelines in English which put the punctuation outside the quote). You can then have another punctuation symbol outside the quote:

"I am very cool 😎", she said.

Then he said, "I am also very cool 😎".