If it degrades the user experience so much that the page is unusable, it's not serving the intended purpose. Users will block the ads or not bother waiting for

If it degrades the user experience so much that the page is unusable, it's not serving the intended purpose. Users will block the ads or not bother waiting for the page to load. Some ads/buttons/analytics code is worth it, but most content sites don't seem to think about the tradeoffs at all.