Panels, Blocks, Layouts, and Drupal 8

Addison Berry writes on "Panels in core" or "Blocks everywhere" or "Layout all the things!" and what this all means:

The end goal basically boils down to two main pieces: turn all page output into blocks (using the new plugin system), and add a new layout system that will allow site builders to control their pages. Pretty awesome, huh? Also, a lot of work.

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With plugins in core, the next step was to get all of the existing Drupal blocks switched over to the new system. Using the plugin system turned the old, pokey core blocks into flexible super-blocks. This allows us to to do cool things like have multiple instances of a block. This was a huge amount of work by a lot of people. It took about a year to get the "blocks as plugins" foundation in place.

Good update and overview on what's behind the changes in Drupal 8.