chore: update README.md (#178)

Co-authored-by: Vigith Maurice <vigith@gmail.com>
Signed-off-by: Derek Wang <whynowy@gmail.com>

README.md

@@ -8,9 +8,8 @@
 
 ## Summary
 
-Numaflow is a Kubernetes-native platform for running massively parallel data processing and streaming jobs.
+Numaflow is a Kubernetes-native tool for running massively parallel stream processing. A Numaflow Pipeline is implemented as a Kubernetes custom resource and consists of one or more source, data processing, and sink vertices.
 
-A Numaflow Pipeline is implemented as a Kubernetes custom resource, and consists of one or more sources, data processing and sink vertices.
 
 Numaflow installs in a few minutes and is easier and cheaper to use for simple data processing applications than a full-featured stream processing platforms.
 
@@ -21,6 +20,12 @@ Numaflow installs in a few minutes and is easier and cheaper to use for simple d
 - Exactly-Once semantics: No input element is duplicated or lost even as pods are rescheduled or restarted.
 - Auto-scaling with back-pressure: Each vertex automatically scales from zero to whatever is needed.
 
+
+## Data Integrity Guarantees:
+- Minimally provide at-least-once semantics
+- Provide exactly-once semantics for unbounded and near real-time data sources 
+- Preserving order is not required
+
 ## Roadmap
 
 - Data aggregation (e.g. group-by)