i.e. -> id est. Usually translated to English as "That is". Implying that subject is the definite case.

Stealing from wiktionary: "The three U.S. states on the west coast have mild seasonal variations in temperature (i.e., warm winters and cool summers)."

e.g. -> exempli gratia. Usually translated to English as "For example". Implying that the subject is simply one example of many.

Stealing from wiktionary again: "Continents (e.g., Asia) contain many large bodies of water."

Ah, right, no. "i.e." is an abbreviation for the Latin "id est", meaning "that is".

"For example" would be "e.g.", ("exempli gratia" in Latin.)

"E.g." is illustrative, whereas "i.e." is exhaustive.

I hadn't heard "i.e." expanded to "in example" before - that explains one source of misunderstanding (despite being grammatically incorrect in its own right).

Edit: It seems you've since been unfairly downvoted for explaining what you meant. Please folks, don't do that. I asked the question, and @fraserharris answered honestly.

I forget where I picked this up, but I use the following to keep them straight:

i.e. == in essence

e.g. == example given

I can never remember the Latin, but in my mind, I usually substitute i.e. to mean "in essence" and e.g. as "e.g.xample" to remember which means which.

So THAT is why many people get it so wrong. I never understood (as a non-native speaker from a 24h country, I still struggle with pm/am and have to look it up every time, so I get why other non-natives may mix it up, but I'm seeing I.e./e.g. confusion mostly among native English speakers... for whom the Latin origin must be a similar situation I now realize).

ie means id est (that is).