PASSED Manual Testing following the steps in the description.

Fixed on:
Tomcat 7.0 + MySQL 5. Portal 6.1.x CE GIT ID: 683117e00e100b585331a0b3c859b3eb5bfe633c.

Steps for testing:
1. Add web content display portlet.
2. Add a new web content.
3. Click configuration of the portlet, enable comment.
4. Click the Subscribe to Comments button.
5. Check the database, in "subscription" table, there is a entry.
6. Delete the web content.
7. Refresh the table, the entry will still be there.
8. Add another web content.
9. Set it to display in web content portlet.

The result on 6.1.x CE was the button show as "Subscribe to Comments". If user click Subscribe to Comments button again, there will be another entry.
But the result on trunk, when the step 7, the entry in database was deleted. After step 9, the button show as "Subscribe to Comments" and if user click Subscribe to Comments button again, there will be a new entry.

FAILED Manual Testing following the steps in the description.

Failed on:
Tomcat 7.0 + MySQL 5. Portal 6.1.x CE GIT ID: 4dab0f42a0db0e2782e82ed6c8108738dcefd58b.

PASSED Manual Testing following the steps in the description.

Fixed on:
Tomcat 7.0 + MySQL 5. 6.1.x GIT ID: 30bbc6e1ff249f4ae700bfa68f3dc6956a3db978.
Tomcat 7.0 + MySQL 5. 6.2.x GIT ID: 1409ab9acfac02810f41479f1e57ce1e621215c4.

Ginson,
Here's new commits:
6.1.x GIT ID: aa7e23951f9811dc60a524bf37e839a9d4eb8649.
6.2.x GIT ID: c31e89cfe4ad618c82678ddb1747dcd8ccd55287.

Thanks,
Jang