User blog comment:Brandon Rhea/Bringing down the banhammer: Best practices for blocking/@comment-4674838-20120318160436/@comment-20644-20120318171359

I would try to stick with the 1 on 1, and I would also try to leave as few messages as possible. Helping them is a good thing, like I said, but if you have to constantly leave messages in a short period of time, even if you feel you should and the user needs to hear it, then all of those messages could make the user feel like they're being bombarded with criticism.

Fewer but longer messages would, in my view, be better than more but shorter messages. That way the user isn't constantly getting the new messages bubble and thinking "Oh great, what now?" That mindset is liable to scare someone off.