Question: How to create host named site collections?
Answer: Create host-named site collections using PowerShell
The management shell in SharePoint 2010 provides a comprehensive set of Windows PowerShell cmdlets that make development, implementation, and management of SharePoint 2010 easier and more effective. The SharePoint management shell replaces the Stsadm.exe management tool. All current and upcoming development of command-line resources and management information in Microsoft SharePoint Foundation 2010 should use this new scripting technology.
However, in order to create named site collection we can make use of the same SharePoint management shell. Following is the way to go:
Create host-named site collections using PowerShell:
Open up the SharePoint 2010 Management Shell and enter the following commands to create a new site collection for each of your desired vanity (Self-love) URLs. In this case I have created a site collection with the host name portal.machsol.com
New-SPSite http://portal.machsol.com -OwnerAlias DOMAIN\username -HostHeaderWebApplication http://web-app-url.com