Well, as much i like this plugin, i still had to uninstall it because it was causing duplicate content on my site. i don't know if it's only on my site or others have the same problem like i do. Example;
Let's say this is a webpage on my site; http://www.example.com/samplepage/
WP-Email recreates it's message url as http://www.example.com/samplepage/email/
Unfortunately, some weeks after installing the plugin, i found in google search results the pages with the email url(www.example.com/samplepage/email/) instead of the main one.
I checked from my google webmaster tools and found out that google had listed over 70 pages as duplicate contents.
I wish to draw the developer's attention to this, as i said earlier i don't know if others are experiencing the same problem or not