What is Ip Hijacking and how is it done ? 192.205.33.145 Uknown 4.68.127.110

What is ip hijacking and how is it done? Sure it would be easy if you were just down the road in burnaby from the Telus Tower on a intersecting trunk with all isps , but what about the layman, could he do it?
The problem with forging ip address's is that its only a one way trip, sure anyone could say that they were someone else but only on the header packet of TCP and not on the reply ping that the packet would go back and just get lost hammering a unexpecting host somewhere.

I guess this is a impossible task since anyone could say they were someone else on the internet but isn't this the case of the search engine giants? Don't they use these empty netblocks to fake huge amounts of traffics to make websites look busy? Yes its illegal but its common place in certain internet circles.

What is a Spinbox?

Grade 10 ? Maybe I only have Grade 8 Education , typically the strongest bolt in any hard and dense operation.