Clarify mobile proximity payments use case.
--- a/latest/use-cases/index.html Thu May 21 15:32:06 2015 -0400
+++ b/latest/use-cases/index.html Fri May 22 21:41:33 2015 -0400
@@ -847,7 +847,9 @@
<dt>Mobile</dt>
<dd>
Daniel takes a taxi from the airport to his hotel. The taxi driver
-displays the total with his mobile device and offers a tap-to-pay option.
+displays the total with his mobile device. Daniel and the taxi driver
+touch their mobile devices to each other. The total appears Daniel's mobile
+device.
</dd>
<dt>Goals</dt>
<dd>
@@ -856,8 +858,8 @@
</dd>
<dt>Motivation</dt>
<dd>
-Unifying the way tap-to-pay offers work with the Web Payments architecture
-would help ensure ubiquity.
+Unifying the way proximity mobile offers work with the Web Payments
+architecture would help ensure ubiquity.
</dd>
<dt>Accessibility</dt>
<dd>