As more and more people make the switch to smart phones they are starting to make fewer phone calls. Since it is now very easy to send an email no matter where you are, that is the option that most people are going with. There are several good reasons for doing this and most data plans encourage it. That being said there are some reasons that this change may be a bit of a problem that will need to be addressed.
The reason that most people are making fewer calls and sending more emails is cost. In large part this is the same phenomenon that resulted in the huge popularity of text messaging. Most plans charge you more for making calls than for sending emails so there is an incentive to communicate in this way rather than calling. The difference in cost can be huge so if you have to communicate a lot you will find that sending emails is a much cheaper option than making a phone call.
A lot of people are also sending emails to save time. If you make a phone call you are likely going to get engaged in a conversation that could take considerable time. Even if the time for each call is fairly short if you have to make a lot of them it will take quite a bit of time. Most people will find that it is much faster to send an email than to make a phone call. This is especially true if you have to send the same message to several different people, one email can be sent to all of them.
Email can also be useful because it allows you to think about what you are going to say. This is especially important if you are sending the message for business purposes. You have time to think about what you are going to say and to make sure that you phrase it just right. You don't have that ability when you make a phone call and that could lead to you forgetting an important part of what you wanted to say or even worse saying the wrong thing altogether. This could be disastrous in some situations so it is often better to send an email.
One last reason that a lot of people are sending emails rather than calling is a little bit less positive. Many people these days do all of their communicating through things like email and text messaging. Many of them have thousands of online friends but are completely unable to communicate with people in the real world. The simple ability to carry on a conversation is something that a lot of people struggle with these days. Being able to send an email allows them to avoid having to talk to people which just makes the problem worse.