Registration is not required to read or comment on blogs hosted on the site, except if chosen by the blog owner. Registration is required to own or post in a weblog. All the basic and original features of the site are free-to-use. However, some features are not available in the free plan: install PHP plugins, customize theme CSS, write JavaScript, domain mapping, domain registration, removal of ads, website redirection, video upload, storage upgrades.
If the free plan is in use, readers see ads on WordPress.com pages, though WordPress.com claims that it is rare.[16][17] On its support pages, WordPress.com says it “sometimes display[s] advertisements on your blog to help pay the bills”. In order to remove the ads, users need to purchase a Plan that starts at $4 a month (if billed annually).