Recovered from the Wayback Machine.
In the previous posting, Dave attached a comment that returns us to the conversation about centralization. However, I don’t expect that we’ll generate any definitive answers to “what is centralization”, as the folks who are interested in distributed systems and P2P have been working this issue for years, with only qualified success.
Centralization hasn’t as much to do with technical points of failure or with issues of deployment as it has to do with control. Centralization implies a single point of control residing in an authority other than yourself.
Is weblogs.com centralized? Yes, from both a control as well as a technology perspective.
Webloggers can automatically invoke the weblogs.com web services, or use the weblogs.com form to invoke the services manually. If the weblog has changed, the blogname and URL are added to the publicly accessible changes.xml file, and eventually to the weblogs.com HTML page. It remains on this page for three hours.
Both the HTML page and the associated XML file and supported services provide a single location to check for recently updated weblogs — a useful technology. However, this single location also leads to the service’s vulnerability.
If the server goes down, weblogs.com is no longer accessible. Dave provided a temporary backup location but if you’re dependent on automated processes to look for the updated information the temporary location didn’t work for you (not unless you wanted to modify your application to point to this new location).
The downtime with weblogs.com last week demonstrates a technical point of failure for a centralized application. There are mechanical methods one can take to avoid this such as the use redundant backup servers, as well as the use of banks of servers. However, as we’ve seen with DoS (Denial of Service) attacks, if there is a determined foe any centralized service can be brought down.
The possibility of technology failure doesn’t concern me in regards to centralized services, as for the most part, this isn’t an issue. As we’ve seen, weblogs.com has rarely been down in the past and the only reason we’re more attuned to the issue now is because of the rather lengthy downtime of the service this last week. Redundant backup servers would have prevented this, but as Dave has said, Userland is a software development company not an ISP. Backup servers are expensive and weblogs.com is a free service.
What does concern me about weblogs.com is the control: Userland has complete control over who shows on this list. And Dave has written filters for this list, as he’s discussed, openly, at Scripting News. (Though these filters may have been removed.)
That’s the danger of centralization.
Are there alternatives? Sure, there are other centralized locations of weblog updates. However, these are also subject to the same technical point of failure as well as issues of control.
Trying to decentralize a service such as weblogs.com would require a new infrastructure overlayed on top of the existing Internet to support the concept of centralized services that are decentralized — in other words to support supplying and consuming information about recently updated weblogs at a single point, the location of which can change from day to day, minute to minute.
Semi-decentralized applications such as Kazaa and Napster don’t provide the technology to solve this problem; they aren’t providing access to centralized resources, they’re providing access to files that can be located on any number of machines.
Until such an infrastructure is in place, we’ll continue to use weblogs.com and benefit from the service, while understanding the limitations inherent with centralized services such as this.
Returning to the comment in the previous post, Dave also mentioned the hypertext link. Now the simple hypertext link truly is a decentralized technology.
Anyone can put a link into their weblog. There is no authority controlling what you can and cannot link to unless you pay attention to the ridiculous and unenforcable “rules” that some web sites publish about deep-linking. Web sites may require permission to access certain pages, but you can place the link on your page — it’s up to the person clicking the link and the web site to negotiate actual viewing of the page.
And if you have a weblog, there is no authority controlling who links to you.
Weblog A links to you and you link to Weblog B, creating an indirect link from A to B. Continuing this process, weblog B links to weblog C and C links to D and D links to E and so on until you have an unbroken chain of weblogging circles forming a living, dynamic community that cannot be controlled and cannot be stopped — not without taking down the Internet, itself. And though some have tried, the Internet is too vast now to be controlled by any one authority.
Centralization. It’s all about control.