As per Zaheed Sabur  updates Google has added a richer hashtag experience to Google Search and this  update is rolling out “within the next few hours” to English language users on google.com and google.ca. As of now this only works for Google+ contents,  And here’s  how it works.

  •  When you search on Google for a hashtag, say [#AmericasCup] or [#WaterfallWednesday], a set of relevant Google+ posts may appear to the right of regular results.
  • You’ll only be able to see posts that have been shared publicly or shared with you.
  • If you click on any of these posts you’ll go to Google+, where you’ll see the full set of relevant posts.
  • You’ll also see links to search for these hashtags on other social sites.