Given the sheer number of weblogs that exist, and more importantly the number of those that could be dead, knowing which weblogs have been updated and when is a critical piece of information. The solution to this problem is a notification service, whereby weblogs alert a system when they’ve been changed. Pioneered by weblogs.com, ping services are the linchpin of every major weblog aggregator.
Nowadays, every weblog author has a number of options to choose from when they setup their blog. The big three are:
There are a number of other ping services for specific communities (e.g. geographic, topical, etc.), but most people decide on the big three. In addition to these choices, the Pingomatic meta-ping service has emerged as a way to easily manage your pinging adventures. Since most of the smaller systems also troll Weblogs.com and Blo.gs, this seems like a suboptimal solution. Why ping 15 individual services when you can ping just one and get the same effect?
As for who receives your ping, Technorati, Bloglines, and Feedster are all closed systems, and pings sent to them are available only to their service. As the weblog economy grows, there will only be more and more competition for each ping, and I assume these companies will protect their data, and for good reason. Any additional updates they get above and beyond the free, open services provide an advantage over other companies. For me, the choice of an open ping system is obvious, but i fear that new webloggers will choose the only name they recognize and many smaller services will lose out at the expense of better-marketed systems.
In the realm of open ping systems, Blo.gs has taken a leap ahead with respect to the efficiency of ping delivery. Most ping services use HTTP as a delivery mechanism, requiring a user to poll a URL to get an XML list of recently updated sites. This is highly inefficent given the nature of the process, namely using a pull technology to push information. Probably due to demand, Blo.gs has moved to a push system whereby blog aggregators can recieve updates as they roll in.
While the future of Blo.gs is unknown, their source code is available, and it has remained a freely available system from the outset. As the author of a blog aggregation system, their efforts have made my life that much easier over the course of the past few years. I sincerely hope that this system, or another open system like it becomes the industry standard for providing update information. Otherwise many of the smaller weblog systems will suffer.