(Affects survival too)
The Bug
As stated a redstone block doesn't power adjacent blocks beneath itself. Instead it powers mechanisms not wire thats 2 blocks beneath it. (meaning a 1 block space between the redstone block and the mechanism.)

Steps to Reproduce
1.) Place a redstone block.
2.) Surround the block entirely with pistons until any more placed will not activate
3.) You can recognize the pistons beneath the redstone block(in a upside-down t-shape starting from the redstone block) are powered. The block is supposed to power all adjacent parts (Explained later in the Explanation paragraphs). The adjacent parts are powered (As explained by the definition adjacent) yet includes pistons that are not directly connected to the redstone block. (This disobeys the definition of adjacent.) For more info please see the first and 3rd attachment, OR ask for more data or a clearer depiction.

The Explanation

When i figured this out, i checked the wiki and mcspotlights video on the block, and none of them say anything about the block powering redstone 2 blocks down(and 1 to the left and right below the source block), just about it powering all adjacent spaces. However any mechanism that's either directly below and spaced 1 block from the redstone block or diagonally below extending 1 block, it powers itself.

I realized that this 'property' of the block completely destroys the function of it in vertically(Facing the sky is the extension direction) positioned pistons as it can power the piston when its extended even if the source for powering it is off because of this 'property'. This is the first thing that told me that this might be a bug. (Not only that but the fact that there were 100's of other issues relating to the piston problem)

I checked the definition of adjacent from my old geometry cards and they state that adjacent is being right next to. This further confirmed this as a bug since no source I've seen has identified the redstone blocks powering adjacent spots In addition to powering mechanisms that appear to be powered by another redstone block right below the first one. (See image 2 and 4 if needing more clarification)

This is the end of the bug report.

~Jouster500

P.S. Multiple issues of a 'proposed' bug that most people have reported were on the vertical piston setup which hinted to the actual problem here. They were duplicates of MC-108. If and assignees believe this to also be a duplicate, then please allow me to say that 1.) the search feature has shown no results to the title which i have named this issue, 2.) the result of the bug report in MC-108 reports on the redstone mechanics of 1.4.5, Not the most recent 1.6.2. Any claim that this is duplicate of that issue report is false as that issue report is outdated due to its incapability to explain the problem with a vertical (Skyfacing) piston setup with redstone blocks.

_Attachment Descriptions _

The first photo displays the powering of sticky pistons by a redstone block. The extended blocks are marked with green wool.

The second image displays the powered areas of a redstone block with pistons in the air.

The third image displays the redstone block not powering the redstone dust which would power a mechanism instead if replaced.

The fourth image displays the vertical and horizontal (Respectively) power spots of the redstone block. The white wool represents the powered spots.