To use questiong for link building is a good tip. There is lots of Question and Answer Websites out there and even more forums where you can post your question and aswers with links to your website :-).
Some of SEO Wil Reynolds favorite and most high quality link building opportunities – a lot he has not shared before publicly. Thanks to Wil Reynolds! Please have a look on Wils Website too, it’s a very good source for seo knowledge.