One of the coolest things about Twitter, apart from the memes, is that people can add their opinions to trending topics or ideas with the use of hashtags. It helps to add diverse voices and different ideas to a conversation because this leads to a more fulfilling user experience for all. Well, usually it's just jokes and Spongebob memes, but those are great, too.
Brands also cash in on trending hashtags as a golden marketing opportunity, which is understandable. There are some businesses that have really strong Twitter games, so it's hard to be mad at them.
Then there are some brands who fail spectacularly at using trending hashtags.
Like DiGiorno did when it used a trending topic about domestic abuse as an opportunity to promote its pizza.
DiGiorno quickly realized its mistake and apologized on Twitter, but not before people screencapped the error and it was saved in the annals of tweetastrophes forever.