When was the character limit expanded from 140 to 280 characters?

The purpose of a hashtag on Twitter is to categorize content and make it more discoverable to other users who are interested in the same topic or theme. Hashtags are words or phrases preceded by the "#" symbol, which turns them into clickable links that users can click on to see all tweets containing that specific hashtag.

Here are some key purposes of hashtags on Twitter:

1. **Organizing Content**: Hashtags help organize tweets around specific topics, events, trends, or themes. By including relevant hashtags in their tweets, users can connect their content with broader conversations happening on Twitter and make it easier for others to find and engage with their tweets.

2. **Discoverability**: Hashtags make tweets more discoverable to users who are searching for or following specific topics or interests. Users can click on hashtags to view a timeline of tweets containing that hashtag, allowing them to explore related content and join conversations around shared interests.

3. **Joining Conversations**: Hashtags provide a way for users to join ongoing conversations and participate in broader discussions happening on Twitter. By including relevant hashtags in their tweets, users can contribute to larger discussions, share their thoughts or opinions, and engage with other users who are talking about the same topic.

4. **Event Promotion**: Hashtags are commonly used to promote events, campaigns, or initiatives on Twitter. Event organizers and participants can create a unique hashtag for their event and encourage attendees to use it in their tweets, allowing them to share updates, photos, and experiences related to the event in real-time.

5. **Branding and Marketing**: Hashtags are also used for branding and marketing purposes on Twitter. Brands, businesses, and influencers often create custom hashtags to promote their products, campaigns, or brand identity, allowing them to generate buzz, increase brand visibility, and encourage user engagement.

Overall, hashtags serve as a powerful tool for organizing, discovering, and participating in conversations on Twitter. They help users connect with others, share content, and engage with topics of interest in a dynamic and interactive way.