If someone is 'ITK' it is because they will either work at a club very high up or know someone who does. Or, less likely, they know a football agent.
Reading back through that twitter feed, he claims to know the transfer budgets and targets of several clubs and the thoughts of several payers - under many different agents.
So the question is - how can one person be so well connected? My opinion is that they can't - and the fact the guy hasn't posted 1 unambiguous and correct piece of info before any newspaper/forum rumours is evidence of that.