Keith O Hudson

To my great dismay, I am finding that almost no one, even sharepoint consultants and sharepoint hosting providers, understand the difference between a subsite and a site collection, and why it should matter.

In Sharepoint 2007 and 2010, a Site Collection is a collection of sites sharing a common set of permissions, content types, and site columns. It was also the case in Sharepoint 2003, but according to this blog, Sharepoint 2003 hid that fact from users so they were actually using Site Collections without knowing it.

A Site Owner can break inheritance and thus manage site permissions individually on subsites, and there are sometimes good reasons to do so.  However, in a test or development environment , I would argue that it is NEVER advisable to break inheritance and have mixed permissions within a Site Collection, unless it is absolutely unavoidable for the solution you are developing.

Here’s why.  Content Type, Site Columns and Permissions are all handled by Sharepoint at the Site Collection level.  If someone working on Subsite A makes a mistake and makes unwanted changes to a Content Type or Site Column within Subsite A, those changes affect all the other subsites within that collection as well.  To return Subsite A to its default state and start over, it would be necessary to delete ALL the subsites, and recreate the entire Site Collection.

If each project is housed within its own Site Collection, such mistakes (very easy to make for someone learning Sharepoint’s out of the box features) are relatively easy to correct.

Of course, a developer who doesn’t know how to use Site Columns and custom Content Types from the Sharepoint GUI may not have this problem, but then, he or she is probably building a solution that will require you to bring a developer back in to fix the solution next time you apply a patch or upgrade to a new version of Sharepoint.

Just my opinion.  What do you think?