Is the mailbox an instant messaging tool?

For example, Netease mailbox is just a communication tool, and Netease Bubble is an instant messaging tool, but if your Netease mailbox has the service of instant notification by SMS, it is instant, which is not much different from instant messaging tools.

Instant messaging (IM) is a terminal service that allows two or more people to communicate with each other instantly in the form of text messages, files, voice and video. Instant messaging can be divided into enterprise instant messaging and website instant messaging according to the purpose of use, and can also be divided into mobile instant messaging and PC instant messaging according to the loading object. The representative of mobile instant messaging is the instant messaging of short messages, websites and videos, such as YY voice, QQ, MSN, Baidu Hi, Universal Communication, Ali Want Want, Wang Jingdang Cecilia Yip, Shangxun BB, Netease Bubble, Netease CC, Shanda ET, China Mobile Fetion, Enterprise Fetion, COCO and other application forms.