Why are there so many different ways to build a paling fence listed on the Internet ?   Because there are actually different types of paling fences and construction methods.

Lapped Paling Fence common in Victoria - palings are over lapped, provides good privacy. 

Construction methods for Lapped Paling Fence

Picture of lapped paling fence - palings one one side, posts the other
Picture of lapped paling fence - capped, palings one one side, posts the other
Picture of lapped paling fence - capped, exposed posts
More paling fence pictures

Butt Paling Fence common in NSW and QLD
Palings are butted up together or have a space between them.
Provides air flow but not privacy. 

Lapped and Butt paling fencing can be constructed in many different ways and with a variety of material sizes.
With or without plinths (plinths can be more than one high).
With or without capping.
With or without trellis.

Timber Fencing Industry survey