I will help interpret this:
The big money moves the stock. Institutions, and large investors, sometimes both.
This is showing "the big boys" are buying. Not a whole bunch of little ones..but the big boys.
The big boys have lawyers, financial consultants, and resources we do not have. That is not to mention the big players often know each other and feed off each other.
This is my main reason for buying: The biggest: Ackman and Berkowitz. Remember Berkowitz has been named as "heir apparent" to Buffet. He is not perfect, but he proabably has the next best investment record history, next to Buffet.