Drupal 8 core has removed many of the "info" hooks and converted them to plugins.

hook_block_info() gone

hook_entity_info()? gone.

hook_field_formatter_info()? gone.

hook_field_widget_info()? gone.

hook_image_toolkits()? gone.

This session will be a practical discussion of how plugins work and how to upgrade your module to Drupal 8 if it used one of these hooks that's been converted to a plugin. In addition I'll cover the essentials of implementing your own plugin if your module previously used an "info" hook and you want to join the new paradigm.

There are definite advantages - including never implementing one of these hooks by mistake again when you're writing a function in your module.

PDF of presentation slides:
https://groups.drupal.org/files/pwolanin-2013-09-info-hook-plugin-d.pdf

Demo code used for this presentation:
https://drupal.org/sandbox/pwolanin/2087657