Here are a few pretty cool tricks I learned at Blue Glass (an SEO conference in Tampa, Florida) when it comes to creating social triggers and online conversations.
First, spend less time creating content and spend more time promoting content. This is especially true for firms that crank out the content ever day. It's like content puke. However, none of the content properly shared and readers don't have enough time to digest the information and engage in a conversation before drowning in another piece of content by the same firm. Find that middle ground of creating and promoting content.
Second, create a controversy and allow people to argue about dumb things. This is easy. State your point of view on something and let it ride. Those commenting on your thoughts will start battling it out with each other on your Facebook page, blog, forum, etc.
Third, find two audiences and pit them against each other. For example, create a conversation about two sports teams; politics; food; exercise; healthcare, etc.
Fourth, draft behind topics or ideas. If a news item or topic is hot, join in on the conversation and write a blog post about how it effects your business or your industry.
None of the above strategies will work until you start creating content. Don't go overboard and create too much. Unfortunately, we see a lot of businesses that don't create enough content (or usually none at all).