diff --git a/README.md b/README.md
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+++ b/README.md
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 # average
 
 Calculate the average of a sequence and its error iteratively, using constant
-memory.
+memory and avoiding numerical problems. The calculation can be easily parallelized
+by using `Average::merge`.
 
 [Documentation](https://docs.rs/average) |
 [crates.io](https://crates.io/crates/average)
 
 [![Build Status](https://travis-ci.org/vks/average.svg?branch=master)](https://travis-ci.org/vks/average)
+
+## Advantages over naive calculation of average and variance
+
+* Avoids loss of precision due to cancellation.
+* Only needs a single pass over the samples, at the cost of a division inside the loop.