I have two site collections (A and B) belonging to the same content database. Inside site collection A there is a list "List1".. now i want to have the same list in the site collection B such - if there are any changes made to the list 1 in site collection A the same changes should b reflected in list1 inside site collection B - is this possible?
You can do it many ways:
- As Vardhaman suggested, use appropriate Item event handlers
- Using Item Created, changed, Deleted workflows
- Timer job which will periodically sync both lists.
Steps 2 & 3 will give control to users for manually syncying at anytime
What kind of changes are we talking about?
If by changes you mean syncing of items, then you can simply write Item Receivers on List A for the
ItemUpdated events. When any of these events occur in List A, these receivers will open up SiteCollection B and inside that open up List B and do the necessary changes.
Here is a comprehensive guide on writing event receivers: