Unfortunately the Flattr button can't be added to all sites, but don't worry with our browser extension you can not only flattr on pages with buttons but also on these sites:
Twitter Instagram SoundCloud GitHub 500px Vimeo App.net Flickr YouTube
If you use a browser not supported by or extension or don't want to install it you can instead use our bookmarklet.
To use the bookmarklet drag this bookmark to your bookmarks bar. Then when you are on a page that you would like to flattr just simply click the button and you will go to the Thing.
Flattr ← Drag this bookmark to your bookmarks bar.