Avian’s Blog

Webmention is a standard that attempts to give plain old web pages some of the attractions of big, centralized social media. The idea is that web servers can automatically inform each other about related content and actions. In this way a post on a self-hosted blog, like this one, can display backlinks to a post on another server that mentions it. It also makes it possible to implement gimmicks such as a like counter. Webmention is kind of a successor to pingbacks that were popularized some time ago by Wordpress. Work on standardizing Webmention seem to date back to at least 2014 and it has been first published as a working draft by W3C in 2016.

I've first read about Webmention on jlelse's blog. I was wondering what the adoption of this standard is nowadays. Some searching revealed conflicting amounts of enthusiasm for it, but not much recent information. Glenn Dixon wrote in 2017 about giving up on it due to lack of adoption. On the other hand, Ryan Barrett celebrated 1 million sent Webmentions in 2018.

To get a better feel of what the state is in my local web bubble, I've extracted all external links from my blog posts in the last two years (January 2018 to January 2020). That yielded 271 unique URLs on 145 domains from 44 blog posts. I've then used Web::Mention to discover any Webmention endpoints for these URLs. Endpoint discovery is a first step in sending a notification to a remote server about related content. If that fails it likely means that the host doesn't implement the protocol.

The results weren't encouraging. None of the URLs had discoverable endpoints. That means that even if I would implement the sending part of the Webmention protocol on my blog, I wouldn't have sent any mentions in the last two years.

Another thing I wanted to check is if anyone was doing the same in the other direction. Were there any failed incoming attempts to discover an endpoint on my end? Unfortunately there is no good way of determining that from the logs I keep. In theory endpoint discovery can look just like a normal HTTP request. Many Webmention implementations seem to have "webmention" in their User agent header however. According to this heuristic I did likely receive at least 3 distinct requests for endpoint discovery in the last year. It's likely there were more (for example, I know that my log aggregates don't include requests from Wordpress plug-ins due to some filter regexps).

So it seems that implementing this protocol doesn't look particularly inviting from the network effect standpoint. I also wonder if Webmentions would become the spam magnet that pingbacks were back in the day if they reached any kind of wide-spread use. The standard does include a provision for endpoints to verify that the source page indeed links to the destination URL the Webmention request says it does. However to me that protection seems trivial to circumvent and only creates a little more work for someone wanting to send out millions of spammy mentions across the web.