This blog posting applies to Microsoft Office SharePoint Server 2007.

By default, in Microsoft Office SharePoint Server 2007 (if you are using the Corporate Intranet Portal template as your default site) when you go to the “Sites” link and click the Create Site button…SharePoint creates a subsite as a member of your portal’s site collection.  This is great if within your organization, you want to easily share things such as templates, site columns, content types and navigational elements. Plus security and user management is much easier using this approach.

However some organizations will still require unique site collections since their business units are very unique and very little sharing is anticipated between groups. If that is the case, then you may instead wish the Create Site button to create site collections. To do this, you need to:

• Enable Self Service Site Creation in Central Administration
• Change behavior of the Create Site button on Site Directory

Enable Self Service Site Creation in Central Administration

1. Open the Central Administration site
2. Click Application Management
3. Click Self-service site management
4. Select the correct web application (that step is easy to miss)
5. Select On for Enable Self-Service Site Creation and click Ok.

Change behavior of the Create Site button on Site Directory

1. From the portal, use the Site Actions menu, select Modify All Site Settings. If you are not on top level site you will need to go to Top Level Site Settings.
2. Under site collection administration, select Site Directory Settings.
3. Select the checkbox to create new site collections from sites directory.

 Gavin Adams describes how to manage permissions for Self-service site creation.