Blocksy comes with a set of cool widgets like: Posts, Social Icons, About Me, Contact Info, Facebook, Advertisement, Quote and more to come soon. All these widgets will become available after you activate the Widgets extension.
To activate it, simply go to WordPress Dashboard → Blocksy → Extensions and click the Activate button on the Widgets extension.
If you go to Appearance → Widgets you will see your new widgets in the Available Widgets section.
The Mailchimp Subscribe widget will appear only after you activate the appropriate extension from the Blocksy dashboard.