Updated more detailed specification of Calendars.

diff --git a/SocialFeaturesMelangeGSoC2010.wiki b/SocialFeaturesMelangeGSoC2010.wiki
index eed3895..6f73b77 100644
--- a/SocialFeaturesMelangeGSoC2010.wiki
+++ b/SocialFeaturesMelangeGSoC2010.wiki

@@ -195,7 +195,48 @@
 -----
 *Suggestion Incorporated* Comment (madhu): For clarity reasons I think it is better to name these values *requested*, *approved* and *declined* since they are not really Boolean fields but a 3-state property.
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+=== Calendars in Detail ===
 
+*UseCases for Different User Roles*
+
+Program Admin
+
+http://www.comp.nus.edu.sg/~savitha/gsoc/cal_init.png
+
+"Initialize Calendars" use case simply refers to the automated creation of a new calendar for each accepted Organization and the assigning of access rights for all the org_admins and students at the start of the program.
+
+*Org Admin*
+
+http://www.comp.nus.edu.sg/~savitha/gsoc/org_admin.png
+
+*Student or Mentor*
+
+http://www.comp.nus.edu.sg/~savitha/gsoc/student-mentor.png
+
+
+*Calendar Types*:
+   * *Program Calendar*: This is a completely public calendar which is visible to all users participating in the program including mentors, students, org_admins and program_admins. 
+   * *Organization Calendar*: Every accepted organization has its own private calendar which is visible only to users working for that particular organization such as mentors, students and org_admin of that organization.
+
+*Calendar Account*:
+    * All the organization calendars and the single program calendar will be hosted in a *single* Google account owned by the program_admin. (this can be the program_admins own account or analternative account such as gsummerofcode@gmail.com where the current program  [http://www.google.com/calendar/hosted/google.com/embed?src=gsummerofcode@gmail.com&ctz=America/Los_Angeles calendar] is being hosted.)
+    * Every org_admin will be given owner access to their org calendar. Google's Calendar API provides access control lists for each calendar. Hence, each org_admin can be given owner  access(user can make changes to events) while org students are given read access(this user can see all event details). (Ref: http://code.google.com/apis/calendar/data/1.0/developers_guide_python.html#SharingACalendar)
+
+*Access Rights for User Roles*
+When users access their Calendars, the respective calendars and rights will be triggered based on the account in which they are logged in. For example, if bob@gmail.com is an org_admin, and is logged in. He will automatically have "owner" access to his org calendar and "read" access to the program calendar.
+
+*Program_Admin*:
+  * Has "owner" access for all org_calendars and program_calendar
+
+*Org_Admin*:
+  * Has "read" access to program calendar.
+  * Has "owner" access to their org_calendar.
+
+*Mentors*:
+  * Has "read" access to their org calendar and program calendar.
+
+*Student*:
+  * Has "read" acess to their org calendar and program calendar.
 
 === APIs & Libraries ===
    * Google Calendars API