# Improving Nextdoor Notification Email Engagement with Generative AI and Rejection Sampling

DevFeed: [Improving Nextdoor Notification Email Engagement with Generative AI and Rejection Sampling](<https://devfeed.tech/articles/let-ai-entertain-you-increasing-user-engagement-with-generative-ai-and-rejection-sampling-20339.md>)

Original publisher: [Read original article](<https://engblog.nextdoor.com/let-ai-entertain-you-increasing-user-engagement-with-generative-ai-and-rejection-sampling-50a402264f56?source=rss----5e54f11cdfdf---4>)

Author: Jaewon Yang

Published: 2023-10-16T17:03:52Z

Content type: article

Language: en

Sources: [Nextdoor](<https://devfeed.tech/sources/nextdoor.md>)

Topics: [Artificial Intelligence](<https://devfeed.tech/topics/ai.md>), [Generative AI](<https://devfeed.tech/topics/generative-ai.md>), [Reinforcement learning](<https://devfeed.tech/topics/reinforcement-learning.md>), [email](<https://devfeed.tech/topics/email.md>)

Tags: [a-b-testing](<https://devfeed.tech/tags/a-b-testing.md>), [ai](<https://devfeed.tech/tags/ai.md>), [building](<https://devfeed.tech/tags/building.md>), [chatgpt](<https://devfeed.tech/tags/chatgpt.md>), [email](<https://devfeed.tech/tags/email.md>), [generative-ai](<https://devfeed.tech/tags/generative-ai.md>), [metrics](<https://devfeed.tech/tags/metrics.md>), [model-training](<https://devfeed.tech/tags/model-training.md>), [notifications](<https://devfeed.tech/tags/notifications.md>), [platform](<https://devfeed.tech/tags/platform.md>), [reinforcement-learning](<https://devfeed.tech/tags/reinforcement-learning.md>)

## AI overview

Nextdoor describes using Generative AI and rejection sampling to improve Notification email subject lines. The approach uses user engagement feedback to produce more informative subject lines intended to increase email opens, clicks, and sessions.

## Source excerpt

Generative AI (Gen AI) has demonstrated proficiency in content generation but does not consistently guarantee user engagement, mainly for two reasons. First, Gen AI generates content without considering user engagement feedback. While the content may be informative and well-written, it does not always translate to increased user engagement such as clicks. Second, Gen AI-produced content often remains generic and may not always provide the specific information that users seek. Nextdoor is the neighborhood network where neighbors, businesses, and public agencies connect with each other. Nextdoor is building innovative solutions to enhance the user engagement with AI-Generated Content (AIGC). This post outlines our approach to improving user engagement through user feedback, specifically focusing on Notification email subject lines. Our solutions employ Rejection sampling [1], a technique used in reinforcement learning, to boost the engagement metrics. We believe our work presents a general framework to drive user engagement with AIGC, particularly when off-the-shelf Generative AI falls short in producing engaging content. To the best of our knowledge, this marks an early milestone in the industry's successful use of AIGC to enhance user engagement. Introduction At Nextdoor, one of the ways to drive user growth and engagement on platform is through emails. One of the emails we have is called New and Trending notifications, where we send a single post that we think the user might be interested in and want to engage with. As part of sending an email, we need to determine a subject line of the email for the email audiences. Historically, we simply pick the first few words of the post being sent to be the subject line. However, in certain posts, these initial words are often greetings or introductory remarks and may not provide valuable information to the user. In the provided image example below, we observe a simple greeting, "Hello!" Figure 1. New and Trending email wher