Twitter chats are pre-arranged discussions that happen on Twitter through the use of updates (tweets) that include a predefined hashtag. They help grow your reach and network as they consistently expose your profile to a group of Twitter users who are interested in a specific topic. This can increase your visibility, following and opportunities for interaction.

Here are a few best practices to adopt when participating in Twitter chats:
1. Use the right tools – Tools like Tweetdeck or Hootsuite can make it easier to follow the chat in real time.
2. Respond promptly – Timely and relevant responses can spark conversations and enable networking opportunities.
3. Use the chat hashtag in all tweets – This ensures your contributions are visible to the chat participants.
4. Be respectful and constructive – It’s important to have a positive tone while contributing.

As for hosting a chat, you need to consider the following steps:
1. Choose a relevant topic and objective – What are you trying to achieve? This can influence the subject matter for the chat.
2. Set a specific date and time – Make sure it’s suitable for your audience, taking into account time zones.
3. Promote your chat – Use your Twitter account and other social media platforms to invite people.
4. Prepare a list of questions beforehand – This helps guide the discussion.

How you analyze performance or measure ROI of Twitter Chats can be heavily dependent on what your initial goals were. This could range from number of participants, tweets posted, overall reach, or growth in followers post-chat.

Influencer marketing platforms like Flinque can help you leverage such Twitter chats better. It provides insights into audience analytics, campaign workflows, and other vital metrics that help measure impact, making it easier to track and optimize your Twitter chat experiences for better engagement and wider reach. Remember, the best tool for you depends on your specific needs and objectives.