Como verás sale la publicidad de wordpress.
Para sacar eso cabe la posibilidad de hacerlo con html?
No debes sacarlo porque va en contra de las condiciones de servicio (ToS) que aceptaste cuando abriste el blog/sitio.
Todos los usuarios con blogs o sitios alojados en WordPress.com deben mantener los créditos de WordPress.com, a menos que hayan comprado el plan Business:
May I remove the Admin Bar, credit links such as ‘Blog at WordPress.com’, theme, font, or toolbar links?
All WordPress.com users are required to maintain the Admin Bar (the dark bar that appears at the top of WordPress.com sites when logged in).
The footer credit can be hidden if WordPress.com Business is active on a site. Please do not use CSS to hide or alter the credits if you do not have the Business plan.
All WordPress.com users can choose among several options for the footer credit, from a minimalist WordPress.com logo to text options like “A WordPress.com Website” or “Powered by WordPress.com.” Please refer to this documentation for further information.
Modifying the style of the footer text (i.e. colors and font size) is fine as long as it’s still readable. Using CSS, you can also add content like a copyright notice to the existing footer. If you would like to do that, you can ask in the CSS Customization forum and Staff or our community volunteers would be happy to help you do that.