docs: add cloud
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-Ory Keto is the first open source implementation of "Zanzibar: Google's
-Consistent, Global Authorization System":
+
+Ory Keto is the first and most popular open source implementation of "Zanzibar: Google's
+Consistent, Global Authorization System"!
+
+## Ory Cloud
+
+The easiest way to get started with Ory Software is in Ory Cloud! It is [**free for developers**](https://console.ory.sh/registration?utm_source=github&utm_medium=banner&utm_campaign=keto-readme), forever, no credit card required!
+
+Ory Cloud has easy examples, administrative user interfaces, hosted pages (e.g. for login or registration), support for custom domains, collaborative features for your colleagues, and much more!
+
+### :mega: Community gets Ory Cloud for Free! :mega:
+
+Ory community members get the Ory Cloud Start Up plan **free for a year**, with all quality-of-life features available, such as custom domains and giving your team members access. [Sign up with your GitHub account](https://console.ory.sh/registration?preferred_plan=developer&utm_source=github&utm_medium=banner&utm_campaign=keto-readme-first900) and use the coupon code **`FIRST900`** on the *"Start-Up Plan"* checkout page to calim your free project now! Make sure to be signed up to the [Ory Community Slack](https://slack.ory.sh) when using the code!
+
+### Google's Zanzibar
> Determining whether online users are authorized to access digital objects is
> central to preserving privacy. This paper presents the design, implementation,
