Hashtags have recently been taken up by Google in a standard search context and in Google+ to give extra weight to search terms. YouTube, Kickstarter, Flickr, Instagram, Diaspora, Pinterest, Tumblr and Gawker all accept hashtags now, as does Facebook, though not as openly. Hashtags are now popularly used for memes that spread across more than one medium, as well as for medium-specific conversations, and they are particularly useful for viral marketing where ideas need to remain linked while spreading as widely as possible.
The most important function of the hashtag is to connect conversations and thereby enable the user to reach new audiences. It can also be used to celebrate or denigrate a particular incident, person or brand, but in this regard it needs to be used very carefully – sometimes businesses using hashtags to try to attract good word of mouth have instead attracted sarcasm or a series of complaints. These can potentially escalate quickly and can be hard to stop. It is particularly unwise to collect all comments using a particular hashtag on a website, as some have discovered too late when accidentally publishing other people’s adverts and negative comments about themselves.
There are three principal ways that hashtags can be used by businesses. The first is for keeping track of trends so that tweets or posts can be tweaked to make them topical, increasing the chance they will spread. The second is for tagging particular marketing campaigns to encourage engagement and to keep track of how they develop. The third is for joining existing conversations that are already getting a lot of attention. Using a hashtag to step into the discussion of a relevant product, service or related theme can provide the opportunity to promote what the business does to new users without coming across as inappropriately intrusive.