An anonymous reader wrote to mention an article over on CNN Money. They go into some detail on what seven years of tinkering
has done for the simple red Netflix envelope. From the article: "Years of experimentation went into creating the perfect DVD envelope. In 1999, Netflix started out with a heavy cardboard mailer. With only 100,000 subscribers, costs weren't a concern yet. Then the company experimented with plastic envelopes, which proved not to be recyclable, and padding, which added too much to postage costs. Both top-loading and side-loading envelopes made an appearance."