http://copperegg.com/
Yet another monitoring app. Copper Egg combines real user monitoring, generic metric logging, server monitoring and maybe other stuff(?) into one application. Pricing starts at $19/month. Not unreasonable.
http://www.strangeloopnetworks.com/
In a similar vein to cloudflare / yottaa, strangeloop offer a performance enhancement service through a physical / cloud based appliance. It uses the standard techniques, js/css combining, sprites, cdn, tailoring to the browser, and so on. No pricing. :-(
http://www.yottaa.com/
Similar to CloudFlare but more expensive ($30/mth no ssl, $130/mth with ssl) it accelerates web sites through the use of CDN, js/css combining, etc.
https://www.cloudflare.com/
loudFlare is an automated CDN / content acceleration type service. It acts as a reverse proxy providing some sort of heuristic security scanning, logging of traffic, and an automatically configured CDN. $15 + $5/site/month.
http://newrelic.com/
A system to monitor multiple aspects of a live application in production including the page load times, server load times, mysql response times, javascript render times, and so on. Expensive.