Vimium - The Hacker's Browser.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Vieb - Browse the web with Vim-bindings
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
cVim - An extension adding Vim-like bindings to Google Chrome.
Better Uptime - We call you when your website goes down