adding content to web 2.0s with senuke and ultimate demon

with either of these tools once i create the web 2.0 accounts can i regularly add more and more content to each site or must i start with a new profile each time?

You can add content to existing profiles with both tools.
In fact that's the best way to do it.
Deep link to internal URL's from different posts on your accounts.

It's MUCH quicker posting as well once the accounts are set up, First time can take a while longer.

Accounts to get deleted, banned, sites go down from time to time, so every so often setting up a new batch isn't a bad idea, but theoretically both tools will allow as much posting as you like.

Same with article accounts, most bookmarking accounts, WIKI accounts, Video submission etc.

Hope that helps.

Scritty