The skinny:
In June 2013, Facebook announced the addition of hashtags to its platform. Hashtags are words or phrases with the pound symbol # at the front of the word , such as #marketing, #lifeisbeautiful, and #follow. The hashtags render the words searchable within the Facebook news feed. This makes profile and fanpage posts containing the words discoverable, leading to potentially more visitors.
Google has also begun to permit hashtags to its Google Plus platform. The hashtags make posts discoverable to Google Plus users, leading to more connections.
Both Google Plus and Facebook, among other platforms, use hashtags similarly to that on Twitter. A hashtag such as #cars would feature tweets and links on the subject of automobiles. Twitter became more associated with "hashtag success" as TV programs begun to host twitterchats during program air time.
The Takeaway:
So hashtags do seem to impact the reach of a post. Inserting them into a few Facebook page posts can improved the reach of the post. I am not sure if engagement is increased. The likelihood of gaining followers is uncertain as well. While Facebook has improved the user interface for Facebook Insights, the metrics do not offer an opportunity to correlate a singular hashtag. Without a plan of hashtag usage, it can be confusing to really discern which hashtag is working.
Some ideas in using hashtags effectively: