We have developed a new plugin that will help you show the addthis.com share tool on your question2answer site.
If you have created a floating share tool, it will show up on the question2answer site.
Apart from that, you can create an in-line tool on the addthis.com dashboard and it will help you encourage users to share their question once they are done posting their question.
Also, you can change the message displaying on the top of social sharing button from the admin panel.
The plugin can be found here:
Feel free to write back if you have any questions or suggestions.