Isnt it always important to know if your website is up or down while you are on a holiday. Atleast for me it is because last week i was not online for 4 days and during this period i used to read mails on my iphone and surf once in a while using the safari browser in it. Most of the times i used to find that my website was up but this does not mean that i can check my blog every minute for the 24 hours continiously. Once there is some downtime i need to either reboot the web server or else contact my server management to look into this downtime issue which can range from php errors, script problems, dns issues, datacenter issues etc.
Anyway check out Host Tracker which is a company which offers you with free website monitoring service with 30 mins interval check up service. Your website is checked for downtime on every interval and the results are saved on their website which you can access anytime by logging in. There are different price plans and in order to test this service i went for the Free 30 days trial where in your website is monitored every minute with reports sent to your on email or else SMS.
You can even add uptime batches if your websites uptime is quite good and if you want to share your monitoring services stats with your website readers.