Was It Up, an online server status checker is now taken offline due to increased burden of keeping it to stay online. It was a good service and i believe everyone who uses this service will also think the same way.
It's a shame that this great service has to go offline until there's a new investor who can fund this project in the future. As for now, i'm using SiteUptime to monitor my server. It's not a real time though since it's a free service. If i choose the pro version, they will have a shorter time interval between each check.
Another service that i use is Pingdom Panel which is more customizable than SiteUptime. It also offers free service where users may add 1 domain and free 20 sms alerts.