Perhaps that would be an easier solution than notifications or marking deleted posts, a read only subforum where all user deleted posts are moved, available for all to read.
We need to somehow see deleted posts because.......
Seriously Theymos, sometimes I wonder if you like having the forum full of scammers. Anyone with a basic knowledge of financial history knew Pirate was a scammer. How much more money would he have succeeded in stealing of participants here if he could delete posts, and use his cadre of believers to keep his threads at the top of the page?
I can see this being abused by scammers.
1. Create a selling/lending topic with normally unacceptable terms
2. delete any posts saying opposing you
3.
4. profit off newbies
if it wasn't self moderated, experienced members can warn new users that the lender is risky, or in case of goods/services, illegal/bogus/fake/ovepriced