Time reflecting incorrectly when made changes to Time Zone in Preferences under My account

Browser: Chrome 20.0.1132.57 m

Can the bug be reproduced: All the time

Description: I logged in, clicked on My account, changed the Time zone from GMT UTC to GMT Eastern Time (US & Canada). Although the changed time was reflecting correctly in chat conversations, but then when I or group members post comments in "My library", "My discussions" or "My groups", the time appears incorrectly. 

Steps to reproduce: 
1. Log in as a new user
2. Click on your user name that will appear on the top left hand side of the page
3. Click on "My account"
4. Change the Time Zone from default GMT UTC to GMT Eastern Time (US & Canada).
5. Click on "Save"
6. Click on "My discussion" to start a new discussion
7. Post a comment

Expected Result: The time should appear as per GMT Eastern Time (US & Canada).
Actual Result: The time appears as per GMT UTC.
![time zone_comments](https://f.cloud.github.com/assets/4551054/579188/a42dd4f4-c86c-11e2-80e1-ade559275818.png)
![time zone_chat](https://f.cloud.github.com/assets/4551054/579189/a81ef3f4-c86c-11e2-8a87-53b5f4624eac.png)