subjects - "Hope" versus "I hope"

Is it correct to use hope without subject? I have seen may times something like:

Hope you feel better soon

instead of

I hope you feel better soon

Is this grammatically correct? Can this be done with other verbs?

Answer

It’s a feature of language known as ellipsis and is indeed found with other verbs. It is frequently used in speech, but it is not appropriate in formal writing.