Question: Do you know of a platform that allows me to create custom channels for my readers to subscribe to specific topics?

If you want a platform to build your own channels so readers can subscribe to particular topics, Contextly could be a good choice. This publisher-oriented content recommendation system uses machine learning and AI to try to keep readers engaged with content the system thinks they'll be interested in. It's got features like channels for subscribing to topics, the ability to spot evergreen stories, and customizable display. Pricing starts at $9 per month for up to 50,000 page views, but you can pay more for larger sites.

Another interesting option is Direqt, an AI-powered chatbot system that's geared for big publishers to reach readers with personalized conversations. Direqt offers a customizable chatbot trained on your entire library of content, including RSS feeds, that you can embed in your site to generate revenue from in-chat ads or paid subscriptions. It's particularly good for increasing audience engagement and generating new revenue.

If you want to build more advanced social networking features, Stream offers a fast and scalable API for building social networks, activity feeds and chat apps. It's got a variety of APIs, including a video and audio API with robust security, and customizable ranking and moderation tools. Stream is designed to be easy to integrate, so it's a good option for boosting audience engagement and building rich social experiences.

Last, Sided offers polling and community software that uses AI to generate polls and encourage audience participation. With features like unlimited polling, lead generation and email click-to-open rate boosts, Sided is designed to boost engagement and give you a better idea of what your audience is thinking. It also includes user profiles, notifications and analytics reporting to help you understand and monetize your community. Pricing starts at $100 per month with a 14-day free trial.