Yes, they do have a lot of sites. Joining is a bit laborious though.
If you really want THE definitive list of spanking blogs, it's at
My Bottom Smarts. Bonnie has over 500 spanking blogs in her blogroll. It's kept up to date, and deleted or silent blogs removed and new ones added weekly.
There is also the Spanking Blog Wiki at spankingartwiki.animeotk.com but it is down at the moment.