Illustration of the Sharing Buttons on WordPress. The screenshot is from my site before I deactivated these buttons. The logos are probably all trademarked by the respective companies.
Many but not all of the images on this blog are under a Creative Commons License. If and only if the image above is under a Creative Commons license, you can find details for the different licenses at the Creative Commons. The most common licenses are Attribution CC-BY 2.0; 2.5; 3.0; and 4.0; and Attribution Share Alike CC-BY-SA 2.0; 2.5; 3.0; and 4.0;