The use of the hashtag grew out of a need to group relevant content on Twitter. In August of 2007, Chris Messina, a blogger suggested using the pound symbol (#) for groups on Twitter. That same year, reached out to Nate Ritter, a California resident tweeting extensively about the wildfires, to use #SanDiegoFire on all his tweets pertaining to the fire. It was such an easy way to find relevant content, that its popularity grew quickly. By 2009, Twitter introduced a search tool and a section on Trending Topics that accounted for the most popular hashtags at any given time. Hashtag use grew in 2010, with the launch of Instagram and exploded when people realized its potential in organizing mass events and popularizing cultural trends.