It is possible to do, certainly. It's probably best at this time that sites like that use Revolution, although there are some interesting developments in Evolution for dealing with thousands of resources.
Yes, that will bog down the Tree. There are several methods to overcome this in Revolution.
1.
Articles - a custom Resource type especially designed for blogging. The individual blog resources are not displayed in the Tree, and are managed in the main Articles resource.
2.
MIGXdb - using a MIGXdb TV to do a simplified version of #1. The child resources are not displayed in the Tree, and are managed through a MIGXdb TV in the parent resource.
3.
MIGXdb-driven CMP - Similar to #2, but using a Custom Manger Page (CMP) to manage the hidden resources.
These "hidden" resources can be accessed using Wayfinder, getResources or any other method used to work with resources. Articles by default sets its child resources to hide in menus, so this needs to be taken into account when using listing snippets - using the &ignoreHidden property in Wayfinder to ignore the "hide in menu" setting for example.
[ed. note: sottwell last edited this post 13 years ago.]