Some handy tools for optimisation
"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil"
There are a raft of tools now available to help a developer to optimise a modern web application: either providing pointers for improvements and modifications of the code or changes that can be made directly to the server (such as enabling mod-spdy). Here are a few that I've found helpful:
Webkit's brilliant inspector
Webkit's inspector is a tool that every developer will likely have to hand, but that many won't know how to use to its full potential. The audit, network and resources panel can be a real help in optimising sites. Majd Taby has recently written a handy guide on how to use some of its panes.
This tool also performs a front-end performance analysis of the site, allowing you to vary the browser and connection routing to check for specific issues or ISP issues. It was recently used to write a performance case study for Github.
A suite of really useful tools to check up on a domain - this site allows one to check a huge variety of crucial metrics, including PageRank and whether one's site has been blocked by the Great Firewall of China.