Welcome to the part of the research. To prove the whole fact that the chat effect sound should be implemented, and by doing that, i decided to create a quick research by asking the people a quick question.
On this little research which i did, was questioned 50 random people who play TFM regulary, and was also being tried to proporcion the female and male amount close to ~25/25.

The question which was asked, is as follows: How often do you skip the messages on your opened tabs?

Of course as this is a research and to track down the right stats for this would be complicated, i also did created 5 answer options to choose from:Never, Rarely, Time by time, Often, Always.
After asking the question to 50 people, the results were this: 6 people did answered Never, 14 people answered Rarely, 10 people answered Time By Time, 13 people answered Often, and 7 people answered Always. To make it clearer for you, heres a chart. (Warning: Big picture incoming & sorry about my editing skills)

So...What can we conclude out of this?Well the conclusion which can be made from this in shorter words is that most part of the people usually dont notice the messages, but the least part of people usually notice the messages, and in result we can conclude that the point of the Sound Effects could come in handy.