1and1 is a hosting service provider, which offers Ecwid as a recommended shopping cart within their site builder.

If you are using 1and1 MyWebsite Plus or Premium package, you can embed Ecwid store into your site easily, following these steps:

1. First of all you will need to create an account in Ecwid (if you haven't already done so). You can sign up for Ecwid account here: http://my.ecwid.com 
2. Then you can embed your Ecwid store into your site or sites. In 1and1 it is done by dragging the Ecwid widget from the toolbar. Click Insert elements, then Products & Documents, then scroll down until you see Ecwid's logo. Then drag that Ecwid widget into the page. 
3. After you have dragged the Ecwid widget from the editor's toolbar into the page in 1and1 site editor, you should see the Ecwid settings dialog

4. In that dialog you need to put your Ecwid store ID into the Store ID field. That will link this widget with your Ecwid account.
5. Save the changes to the page and see it live on the site - the place where you put the Ecwid widget should display the store front.