Usually, there are a bunch of rules and best practices which help optimizing a website, bring new customers, and in general making user experience fast, smooth and pleasant while (sometimes) reducing the server load.
Also, usually, the largest companies don't bother to use those best practices. Except for few companies (like Google), on the largest websites, we can see:
- meaningless errors, annoying popups, register forms with huge amount of fields to fill, UX issues on register¹, stupid questions and situations which make it impossible to use the website², confusing situations on key parts of the website³, multiple redirects, slow pages, etc.
On one hand, those companies are paying a huge amount of money to develop, optimize⁴ and host their websites since their success relies partially⁵ or completely⁶ on it; on the other hand, they are constantly violating the best practices while people advocating those best practices explain that following them helps to achieve better UX and faster websites with lesser footprint on environment (which can be non-negligible on websites hosted on thousands of servers).
In such a case, it is logical to ask:
If the large companies which are really successful, do have a lot of money for their websites and competent employees and which care about website optimization violate constantly those best practices, are those best practices true?
Or, in another words, if those best practices are so important and helps so much to optimize websites, why those companies don't care about them?
Let's take an example of Dell.com. I'm pretty sure they hire the best of the best to create their home page. Their home page use table layouts. Does it mean that people who tell that table layouts are evil are wrong? Does it mean that the best of the best hired by Dell are incompetent?
¹ First example: eBay makes it impossible, when registering, to paste your mail address in both fields, making it longer to use the registration form with no reason at all except to annoy users; best practice would be to forbid copying, but allow pasting. Second example: Microsoft Live limits the length of a password to 16 characters, with no apparent reason at all.
² For example, when you've not being to Amazon for a very long time, it says that the password is invalid, then, to recover it, asks you the information about your last transaction, which makes the account unusable if you've never done any transaction before with the account.
³ Dell, for example, makes it impossible to order a rack server without any hard disk, while this can be perfectly valid if you already have the hard disks you want to reuse.
⁴ Such optimization includes partial flush to send the most important content faster, studies on the relationship between time spent by people waiting for pages to load and the number of people using the website, etc.
⁵ As for Dell, Microsoft and others.
⁶ As for eBay or other web-based companies.