The official line from Google is that sharing buttons like AddThis don’t work with Google Tag Manager because they’re associated with in-page structure. However, many AddThis features can be added to a page with Google Tag Manager.
NOTE: In order to get these examples to work properly you’ll have to replace YOUR-PROFILE-ID with your profile ID, which you can find by logging into your AddThis account and going to http://www.addthis.com/settings/publisher/
Our page-level tools – the Sidebar Share Buttons, related post tools (other than inline, targeting messages, and the Header Follow – will work with Google Tag manager easily. Just create a Custom HTML Tag manager with this code in it:
Our inline tools – like Inline Share Buttons or Related Posts Inline – require HTML on the page that cannot be added with Google Tag manager. This code will have to be added directly to the page.