The last one is K/d.

*Good blog!

You should have been one of the contributors for this post!

Thanks for all the helpful information!

I would also suggest too many and too big media files. Like pictures, music, video, etc. Check your theme design that it does not carry too many big graphic file sizes rlevant to the actual size of the graphic.

External HTTP requests is also a killer. You call it external referencing. But really it is all types of external http requests. These are requests via HTML or Java or some other script to external websites. Here you are at the mercy of the external webserrver and website. Which you have no control over. Allso the extra requests cause extra and time consuming hops over the network to retrieve the data. Lower these HTTP requests if you can.

Slow Database: Well this is a real conundrum. Many databases and thousands of tables can slow a website down. But it's not the datbase alone, but a combination of software, hardware and setup. 1000 databases and tables can run faster than 10 if hosted on a good machine and setup correctly. It also depends of the type and traffic of the sites being hosted. You can get good perormance out of many websites that have low traffic as opposed to fewer websites with huge amounts of traffic.

But Yes your point that shared database hosting can be a killer.

Also rearranging your code can give you the effect of a spedier site. Like putting requests into an iframe, putting such requests at the bottom of the site and dom model. Causeing these scripts to run last, gives the impression taht your site loads faster. Because people will start reading your site when it's finnished loading, unaware that at the end you site is still making external requests.