Saw the above pinger utility written by Corey Goldberg a while ago. It is in Python and is multi-threaded.
Seeing it reminded me of writing a pinger utility some years ago for a company I worked for at the time; it was for Unix systems, and was not multi-threaded.
It was written in a combination of Perl (for regex usage), shell and C.
The C part (a program that was called from the controlling shell script) was used to overcome an interesting issue: a kind of "drift" in the times at which the ping command would get invoked.
The users wanted it to run exactly on the minute, every n minutes, but it would sometimes run a few seconds later.
I used custom C code to solve the issue.
Later I learned (by reading more docs :) that the issue could probably have been solved by calling a Unix system call or two (like gettimeofday or getitimer, I forget exactly which right now) from my C program.
Anyway, the tool ended up being used to monitor the uptime of many Unix servers at the company. The sysadmins (who had asked me to create the tool) said that it was useful.
As Corey says in his post, pinger tools can be used to monitor network latency, check if hosts / devices are alive, and also to log and report on their uptime over an extended period, for reporting and for taking corrective action (as my utility was used).
Also check out pingdom.com for an example of a business built on these concepts. Site24x7.com is another such business; it is part of the same company as Zoho.com. They were (and still are) into network monitoring / management before they created the Zoho suite of web apps.
I use both Pingdom and Site24x7 on my business web site www.dancingbison.com, from over a year or more now, to monitor its uptime, and both are fairly good at that.