An ETag is a signature attached a server response. If the client requests a URL (HTML page, image, style sheet, etc.) whose ETag is identical to the one it already has, the web server will reply that it does not need to download the resource and that it should use the one it already possesses. Using ETags saves huge amounts of bandwidth.

Instead of using a dedicated server for each project, and loading it up to 20% of its capability, pool machine resources through a hypervisor. One physical machine can offer the same service as 4 dedicated servers at 20%. This optimizes the use of the processor and RAM while consuming less electricity than multiple physical servers. This method also reduces the amount of electronic waste (WEEE) generated by the website.