Everything from synchronous to asynchronous communication are tools to help you have access to your students. Now, some of these tools are more effective channels of communication than others. In addition, to several social platforms which can be used to communicate with your students they're aware of these social media outlets like facebook, instagram, LinkedIn, and Twitter now renamed X. Now these are static and the urgency to get in contact with your student is not an active (live) form of communication.
Using a telephone call is just as good to emphasize some deadlines your student may need to keep in mind to succeed in class and give you a chance to avoid late examinations. A quick message to a student can be useful when they know the acronyms for example ttyl (talk to you later) and lol but it should be kept to a minimun bc its nota professional format.
