cho mình hỏi tác dụng thẻ meta này

<meta name="RATING" content="GENERAL" />
<meta name="GENERATOR" content="RongBay" />
<meta name="msvalidate.01" content="340FB83D31B440EF98DD3A4230A61C6A" />
<meta name="verify-v1" content="x2ZsXyFSYALxzSdyxM75hKOYRHlCM3Van3y7bN1+LpQ=" />
<META name="y_key" content="7df7ded10c9a2fb9">

<meta http-equiv="EXPIRES" content="0" />
<meta name="RESOURCE-TYPE" content="DOCUMENT" />
<meta name="DISTRIBUTION" content="GLOBAL" />

 

Bác tham khảo đây thủ -> http://www.metatags.info/meta_name_distribution