Added warning about otel format

docs/articles/metrics-plugins.md

@@ -52,8 +52,16 @@ tags since those are counted as separate metrics. This
 [article by DataDog](https://www.datadoghq.com/blog/the-power-of-tagged-metrics/)
 has some good guidelines.
 
-As of October 2023, we're in the process of becoming an official integration
-with DataDog, which would reduce the way some of our metrics are counted.
+:::warning{title="Metrics Aggregation"}
+
+Your Zuplo API can be deployed to many edge locations. Each location will send
+metrics to DataDog independantly. For low volume APIs this may be okay, but
+typically you will want to aggregate metrics before sending to DataDog. You can
+use a tool like the
+[OpenTelemetry Collector](https://opentelemetry.io/docs/collector/) for the
+aggregation.
+
+:::
 
 ```ts
 import {

docs/articles/opentelemetry.md

@@ -99,6 +99,16 @@ Adding OpenTelemetry tracing to your Zuplo API is done by adding the
 For most providers you will set values for `exporter.url` and
 `exporter.headers`. It's common for providers to use a header for authorization.
 
+:::warning{title="OpenTelemetry Protocol"}
+
+The Zuplo OpenTelemetry plugin only supports sending data in JSON format. Not
+all OpenTelemetry services support the JSON format. If you are using a service
+that does not support JSON, you will need to use a tool like the
+[OpenTelemetry Collector](https://opentelemetry.io/docs/collector/) that can
+convert the JSON format to the format required by your service.
+
+:::
+
 ```ts title="zuplo.runtime.ts"
 import { OpenTelemetryPlugin } from "@zuplo/otel";
 import { RuntimeExtensions, environment } from "@zuplo/runtime";