Google+ introduced hashtags, along with a number of other new features, last month in an effort to make the Google+ feed a little deeper and more interesting. Hashtags on Google+ are very similar to those on Twitter and now Facebook: you can use them to find, start and join conversations about specific topics. However, Google+ hashtags are slightly different to their Twitter counterparts.
The Google+ stream interface allows for different kinds of hashtag engagement than on Twitter: instead of taking you to a different hashtag-specific stream, clicking on a Google+ hashtag will flip you through other similarly hashtagged posts in-stream. Google+ will also show you related hashtags – other hashtags that have been used in posts alongside the hashtag originally clicked on.
Of course, you can search for a Google+ hashtag, just as you would on Twitter, and all the relevant posts will appear in the stream. Google+ gives you the option to arrange hashtagged posts chronologically, or see the “Best of” posts at the top of your stream. I’m not entirely certain what qualifies posts to make it into the “Best of” stream. Supposedly, it takes into account the amount of engagement a post has received and its timing, but it might also – considering it’s a Google product – take SEO into account (after all, Google+ does intuitively search articles for key terms on order to add hashtags).