formatting tweak, added datasource overview blurb.

docs/sources/datasources/graphite.md

@@ -19,7 +19,7 @@ queries through the use of query references.
     > NOTE: If this link is missing in the side menu it means that your current user does not have the `Admin` role for the current organization.
 
 3. Click the `Add new` link in the top header.
-4. Select `Graphite` from the dropdown. (Graphite is selected by default)
+4. Select `Graphite` from the dropdown.
 
 Name | Description
 ------------ | -------------

docs/sources/datasources/overview.md

+----
+page_title: Data Source Overview
+page_description: Data Source Overview
+page_keywords: grafana, graphite, influxDB, KairosDB, OpenTSDB, documentation
+---
+
+# Data Source Overview
+Grafana supports many different storage backends for your time series data (Data Source). Each Data Source has a specific Query Editor that is customized for the features and capabilities that the particular Data Source exposes. 
+
+
+## Querying
+The query language and capabilities of each Data Source are obviously very different. You can combine data from multiple Data Sources onto a single Dashboard, but each Panel is tied to a specific Data Source that belongs to a particular Organization.
+
+## Supported Data Sources
+The following datasources are officially supported:    
+* [Graphite](/datasources/graphite/)    
+* [InfluxDB](/datasources/influxdb/)    
+* [OpenTSDB](/datasources/opentsdb/)    
+* [KairosDB](/datasources/kairosdb)
+
+Grafana can query any Elasticsearch index for annotation events, but at this time, it's not supported for metric queries. Learn more about [annotations](/reference/annotations/#elasticsearch-annotations)
\ No newline at end of file

docs/sources/guides/basic_concepts.md

@@ -9,7 +9,7 @@ page_keywords: grafana, graphite, metrics, query, documentation
 This document is a “bottom up” introduction to basic concepts in Grafana, and can be used as a starting point to get familiar with core features.
 
 
-### ** Data Source 
+### ** Data Source **
 Grafana supports many different storage backends for your time series data (Data Source). Each Data Source has a specific Query Editor that is customized for the features and capabilities that the particular Data Source exposes. 
 
 The following datasources are officially supported: [Graphite](/datasources/graphite/), [InfluxDB](/datasources/influxdb/), [OpenTSDB](/datasources/opentsdb/), and [KairosDB](/datasources/kairosdb)