Agreed. 37Signals generates numerous "lessons learned" posts under the pretense (implied or otherwise) of helping other people learn from their experience. If they don't see it that way, they should add the text "This design is ours and if you copy it or produce anything that looks like it, we'll publicly humiliate you f'ers and insult your investors as well!" to the beginning of each of their supposedly educational posts.
Or, they should spell out the degree to which something has to be changed before they'll be okay with it. Such as "you can put a big customer image on the page because, well, we didn't invent that. You can also put screenshots on the page because, well, we didn't invent that either. And same goes for customer quotes, checklists, and company logos. But we'll take you down if you put checklists with green checks to the right of the giant customer image, a quote to the right of the client's head, and two screenshots below the checklist, etc., etc."
That said, it is an unfortunate that Curebit linked to 37's assets instead of creating their own. And it is clearly a copy beyond just the linked assets. But I don't think it's an international incident on the order of Wikileaks or such. But that's how it's being treated for some reason.
Personally, I would have emailed Curebit privately and asked them to change it instead of trying to tarnish an individual's and company's reputation. That's called "being civil," but that's not how 37Signals works. Remember the time Google created something that resembled Campfire as a demonstration of what Google App Engine could do? It was a 3-pane window with a chat log on the left, the name of the room and a list of people in the room on the right, and a text entry area across the bottom. 37Signals treated it as if they were the first and only company to develop a chat client that worked that way. Here's a link to that incident: http://techcrunch.com/2008/04/08/google-to-close-huddlechat/
Here's the choice (dangling) quote: "we’re just disappointed that they stooped so low to basically copy it feature for feature, layout for layout…We thought that would be beneath Google, but maybe its time to reevaluate what they stand for."
Really?