I am a seven letter word, you read me daily. Letters 567 increase every year. The third and fourth letters are the same and my 325 letters cover about 70% of the world. What am I?

MESSAGE.
Letters 5, 6 and 7 increase every year. This is AGE. Letters 325 cover 79% of the world. This is SEA. Letters 3 and 4 are the same, since the 3rd letter on the second clue is SS, let us assume that 3 and 4 are letters S.