I feel that it is a basic act of courtesy to acknowledge, however briefly, when someone has communicated with you via text message. So if they send me some information, I often will just say ‘Thanks’. If they have made a suggestion to which I agree (“Let’s meet at 10:00am”), I will reply ‘Ok’. If they ask me to confirm some choice (“Shall I come at 10:00?”), I will reply ‘Sure’.
I notice that some of the people will use the thumbs up emoji instead of words. But I am not an emoji kind of guy and felt that my words conveyed the same sense of agreement or acknowledgement.
But I am not an expert on social media communication and recently I was listening to a radio program and someone said that just replying ‘Sure’ was bad, in that it implied sarcasm, as if I had said ‘Yeah, sure’ in a disdainful voice. However, I was assured that ‘Sure!’ was fine.
She then went on to say that ‘Ok’ was even worse than ‘Sure’, which startled me since that is my most frequent from of acknowledgment.
I am not sure how universal this sentiment it. The mores in the world of online communication can change rapidly over time as well as vary a lot from person to person, so maybe ‘Ok’ and ‘Sure’ are ok despite what the speaker said.