update readme with instrumentation limits

Author: djih

README.md

@@ -36,7 +36,18 @@ Amplitude-Javascript
 
 # Tracking Events #
 
-It's important to think about what types of events you care about as a developer. You should aim to track between 20 and 200 types of events on your site. Common event types are actions the user initiates (such as pressing a button) and events you want the user to complete (such as filling out a form, completing a level, or making a payment). Here is our help article on [Event Taxonomy and Best Practices](https://amplitude.zendesk.com/hc/en-us/articles/211988918-How-to-Approach-Your-Event-Taxonomy).
+It's important to think about what types of events you care about as a developer. You should aim to track between 20 and 200 types of events on your site. Common event types are actions the user initiates (such as pressing a button) and events you want the user to complete (such as filling out a form, completing a level, or making a payment).
+
+Here are some resources to help you with your instrumentation planning:
+  * [Event Tracking Quick Start Guide](https://amplitude.zendesk.com/hc/en-us/articles/207108137).
+  * [Event Taxonomy and Best Practices](https://amplitude.zendesk.com/hc/en-us/articles/211988918).
+
+Having large amounts of distinct event types, event properties and user properties, however, can make visualizing and searching of the data very confusing. By default we only show the first:
+  * 1000 distinct event types
+  * 2000 distinct event properties
+  * 1000 distinct user properties
+
+Anything past the above thresholds will not be visualized. **Note that the raw data is not impacted by this in any way, meaning you can still see the values in the raw data, but they will not be visualized on the platform.** We have put in very conservative estimates for the event and property caps which we don’t expect to be exceeded in any practical use case. If you feel that your use case will go above those limits please reach out to support@amplitude.com.
 
 # Settings Custom User IDs #