...

That helps, but I'm more interested on knowing if there is a size issue. Does performance degrade once the database gets to a particular size, for example.

I'm afraid that I don't know, but I'd very much like to ;-) I'm working on the basis that I'll deal with it when it becomes a problem, but I understand that may not be an acceptable proposition in your case

The following may interest you, although I don't know the size of the information stored in Zope.org: http://www.zope.org/AboutZopeOrg

The ZODB deactivates objects that aren't needed. As a result, you couuld have a 1.5Gb ZODB and use a very small amount of memory -- say 40MB. You could have a 200MB ZODB and by virtue of your application design have every object in memory at once -- using say, 250MB of memory. There is no DIRECT correlation between ZODB size and performance and memory use. LOTS (most?) depends on how your particular application behaves. --Rob