You may have recently read Website Obesity by Maciej Cegłowski, as featured on Hacker News. There’s a lot of great stuff in that article. The most obivous and striking thing is that there is a lot of bloat on the web. Examples include a tweet (140 characters) that is served as a 900kB website. How to optimize a website and remove bloat is a topic in and of itself. I can highly recommend the article mentioned above.