When you create a 'standard' blog hosted on 1and1.com then comments and other features (such as classifications) don't work.
If you click on the comment for a post, such as
nothing happens -- you stay on the home page.
This is because there is a mismatch between the contents of the .htaccess file and the permalink option. The blogs are held on a separate server, behind a firewall, so there is no way of accessing them.
Go to the control panel, Options > Permalinks
Select any other permalink option, and press 'Update Permalinks'.
Then reselect the "year/month/day" format, and press 'Update Permalinks' again.
This causes the .htaccess file to be updated, and your comments and other features will now work correctly.