I am new to SharePoint 2010. I would like to know what are My Sites exactly and what are the features they provide? How can we configure them?
The Microsoft Introduction to MySite offers a pretty good description. If you're still confused, think of it like Facebook. Each person has their own Facebook page which is customised according to their needs and can present different information to different groups of people based on configured permissions.
SharePoint MySite are kind of personal sites for all sharepoint users. You can map it with the Profile pages of social networking sites.
this site contains information related to recent activity, collegues, membership and other userful information about sharepoint site users.
Below image can give you some idea about sharepoint my sites.
SharePoint 2010 My Site: link text
Refer to the link given by Ashish above to have some more idea.
you can access this link for configuring my site:
The guide is quite long so I cannot reproduce it here.