Inbox by Gmail has a significant impact on email marketing. You must understand how Gmail's inbox categorizes emails. You face the risk of emails being filtered into the Promotions or Spam tab. Your open rates may drop if this happens. You need to focus on creating valuable content. This can help prevent your emails from being filtered. You also need to build a good sender reputation. This increases your chances of landing in the primary inbox. You must engage with subscribers regularly. This keeps your emails relevant and boosts delivery rates. Gmail's inbox system affects how well your email campaigns perform.