Updated README

README.md

 
 Open the AlwaysKillSticky options window (either by clicking on the AlwaysKillSticky icon in your toolbar, or by going to your Extensions page, clicking “Details”, then clicking “Extension options”).
 
-AlwaysKillSticky can work in either two modes: **blacklist mode** and **whitelist mode**.
+AlwaysKillSticky can work in either of two modes: **blacklist mode** and **whitelist mode**. (You can switch modes at any time.)
+
+### Blacklist mode
 
 In **blacklist mode** (the default), stickies will *only* be killed if:
 
 * the page URL matches one of the patterns in the **matching patterns** list, *and*;
 * the page does *not* match any of the patterns in the **exclusion patterns** list.
 
-Conversely, in **whitelist mode**, the matching patterns list is *ignored*. Stickies are *always* killed, *unless* the page matches one of the patterns in the exclusion patterns list.
+### Whitelist mode
 
-You can switch between blacklist mode and whitelist mode at any time.
+In **whitelist mode**, *the matching patterns list is ignored*. Stickies are *always* killed, *unless* the page matches one of the patterns in the **exclusion patterns** list.
 
 ## License