I feel WordPress is probably the best popular blog website software because of the large number of themes, and Plug-ins for WordPress. There are also a lot of web hosts which work well with WordPress. I haven't seen a lot of blog posts which recommend Joomla, Drupal, and other non-WordPress blog/website software.
Tumblr is now owned by Verizon, so it may become a paid service, or censor or delete content which is not family friendly, or advertisers like toy companies don't like. I feel eventually Blogspot/Blogger.com will not let users posts blog posts which are not advertising friendly, or family friendly because it is owned by Google which sell a lot of ads on its websites like YouTube, Google Play, and Blogger. Google may also someday shutdown Blogspot.com like how they shutdown Google Plus because of Security problems according to Google is shutting down Google+ for consumers following security lapse .
Tumblr is now owned by Verizon, so it may become a paid service, or censor or delete content which is not family friendly, or advertisers like toy companies don't like. I feel eventually Blogspot/Blogger.com will not let users posts blog posts which are not advertising friendly, or family friendly because it is owned by Google which sell a lot of ads on its websites like YouTube, Google Play, and Blogger. Google may also someday shutdown Blogspot.com like how they shutdown Google Plus because of Security problems according to Google is shutting down Google+ for consumers following security lapse .