I mean the server they provide you for uploading data. The "Easy Mode" server is a different server. Advanced Mode is the car where you can open the hood and work on the guts. Easy Mode is the car that has a locked hood and you don't have the key. DreamHost does the maintenance for you on the Easy Mode.
Either way lets you host your blog at example.com, without the need for the "blog" subdomain: blog.example.com. If Easy Mode won't let you type in just "example.com," then something's wrong.
However, down the road, you may wish to open the hood of that car or repaint it. Easy mode lets you choose from a limited set of paintjobs (themes) and options (plugins). If you want more, then you'll wish you went with Advanced Mode.