AFTER 233 years in print, the Observer is set to branch out into a novel medium: the internet. The world’s oldest Sunday newspaper was acquired this week by Tortoise Media, a six-year-old startup that hopes to reinvigorate the reportedly loss-making title. It will start by providing it with a website. As the paper’s new owner yanks the business out of the 18th century and into the 21st, the deal offers a snapshot of how the news industry is changing.