It's an engineering decision - Flikr has to host a large amount of data for very little cost, since most users aren't paying. Space isn't cheap by the Petabyte!
The design for a system where you had multiple redundant copies of all the data and could roll back any changes to the data set is different - and would cost a lot more.
Here is what I don't understand. They have multiple redundant copies in case of unlikely scenario of disaster, but they have no copies or protection in case of quite likely scenario of operator error. This seems backward to me.
EDIT: I don't believe that Yahoo! Flickr does not have a way to recover these things. Or I'm completely wrong.
I think it's likely that Flickr has a way to recover the data but the front line support personnel don't, and they don't want to have some dev spend a few hours to fix a single customer's problem, even if it was Flickr's mistake.
Reverting a full db should be straightforward (stop the db server and revert a dump).
For a single account it's more of a pita.
Retrieving all the datas associated with one account, put it in a format readable from the production environment and recommit all the changes while dealing with the potential errors and inconstencies seems quite a huge deal.
Messing unrelated data in the process would also be a nightmare.
Of course, not deleting anything from the start wouod be the way.
It's trivial in Oracle, just do a Flashback Query. You would just need to support that in whatever front end interface the customer support people use.
I'm very surprised that he wasn't arrested, prosecuted, served with an injunction not to talk about this and have all his computers confiscated.
The lottery commission in BC is on it's Nth major criminal investigation - but the trick here seems to be the simpler method of the shop stealing winning tickets from customers.
I think the idea is to build a community - in order to use SO as more than a Google scrape you need to put in some work and become involved. Then you are more likely to go back and add answers yourself - so you contribute to the collective.
The temporal nature of best practices is my biggest complaint with how SO works. It works great for relatively static subjects, but its useless for fast moving technology targets due to the community resistance of duplicate questions.
edit: I was asked a question which was perfectly answered by rtg. Should've provided more substance, but I wanted to endorse this as being exactly what I was talking about.
I think the Dutch Sandwich is something like - you move all the money to Netherlands, so no tax in the rest of Europe (common market) then to a Dutch owned off-shore tax haven like the Dutch Antilles - so you pay no tax in the Netherlands either.
This is like helping the nerds carry on taking money from the bullies once they grow up and get dead end jobs