I was wrong about robots.txt

This is kinda amusing.

robots.txt main purpose back in the day was curtailing penalties in the search engines when you got stuck maintaining a badly-built dynamic site that had tons of dynamic links and effectively got penalized for duplicate content. It was basically a way of saying "Hey search engines, these are the canonical URLs, ignore all the other ones with query parameters or whatever that give almost the same result."

It could also help keep 'nice' crawlers from getting stuck crawling an infinite number of pages on those sites.

Of course it never did anything for the 'bad' crawlers that would hammer your site! (And there were a lot of them, even back then.) That's what IP bans and such were for. You certainly wouldn't base it on something like User-Agent, which the user agent itself controlled! And you wouldn't expect the bad bots to play nicely just because you asked them.

That's about as naive as the Do-Not-Track header, which was basically kindly asking companies whose entire business is tracking people to just not do that thing that they got paid for.

Or the Evil Bit proposal, to suggest that malware should identify itself in the headers. "The Request for Comments recommended that the last remaining unused bit, the "Reserved Bit" in the IPv4 packet header, be used to indicate whether a packet had been sent with malicious intent, thus making computer security engineering an easy problem – simply ignore any messages with the evil bit set and trust the rest."

I created a search engine that crawled the web way back in 2003. I used a proper user agent that included my email address. I got SO many angry emails about my crawler, which played as nice as I was able to make it play. Which was pretty nice I believe. If it’s not Google people didn’t want it. That’s a good way to prevent anyone from ever competing with Google. It isn’t just about that preview for LinkedIn, it’s about making sure the web is accessible by everyone and everything that is trying to make its way. Sure, block the malicious ones. But don’t just assume that every bot is malicious by default.

Hey OP,

1)

You consider this about the Linkedin site but don't stop to think about other social networks. This is true about basically all of them. You may not post on Facebook, Bluesky, etc, but other people may like your links and post them there.

I recently ran into this as it turns out the Facebook entries in https://github.com/ai-robots-txt/ai.robots.txt also block the crawler FB uses for link previews.

2)

From your first post,

> But what about being closer to the top of the Google search results - you might ask? One, search engines crawling websites directly is only one variable in getting a higher search engine ranking. References from other websites will also factor into that.

Kinda .... it's technically true that you can rank in Google if you block them in robots.txt but it's going to take a lot more work. Also your listing will look worse (last time I saw this there was no site description, but that was a few years back). If you care about Google SEO traffic you maybe want to let them on your site.

I try to stay away from negative takes here, so I’ll keep this as constructive as I can:

It’s surprising to see the author frame what seems like a basic consequence of their actions as some kind of profound realization. I get that personal growth stories can be valuable, but this one reads more like a confession of obliviousness than a reflection with insight.

And then they posted it here for attention.

What astounds me is there are no readily available libraries crawler authors can reach for to parse robots.txt and meta robots tags, to decide what is allowed, and to work through the arcane and poorly documented priorities between the two robots lists, including what to do when they disagree, which they often do.

Yes, there's an ancient google reference parser in C++11 (which is undoubtedly handy for that one guy who is writing crawlers in C++), but not a lot for the much more prevalent Python and JavaScript crawler writers who just want to check if a path is ok or not.

Even if bot writers WANT to be good, it's much harder than it should be, particularly when lots of the robots info isn't even in the robots.txt files, it's in the index.html meta tags.

The problem is the robots that do follow robots.txt its all the bots that don't. Robots.txt is largely irrelevant now they don't represent most of the traffic problem. They certainly don't represent the bots that are going to hammer your site without any regard, those bots don't follow robots.txt.

This article could have been two lines. It takes some serious stretching of school-essay-writing muscles to inflate it to this many pages of waffle.

Having worked on bot detection in the past. Some really simple old fashioned attacks happened by doing the opposite of what the robots.txt file says.

While I doubt it does much today, that file really only matters to those that want to play by the rules which on the free web is not an awful lot of the web anymore I’m afraid.

This doesn't seem like a new discovery at all - this is what news publications have been dealing with ever since they went online.

You aren't going to get advertising without also providing value - be that money or information. Google has over 2 trillion in capitalization based primarily on the idea of charging people to get additional exposure, beyond what the information on their site otherwise would get.

if you are hosting a house party that invites the entire world robots.txt is a neon sign to guide guests to where the beers are, who's cooking what kind of burgers and on what grill; rules of the house etc - you'll still have to secure your gold chains and laptop in a safe somewhere or decide to even keep them in the same house yourself

LinkedIn is by far the worst offender in post previews. The doctype tag must be all lowercase. The HTML document must be well-formed (the meta tags must be in an explicit <head> block, for example). You must have OG meta tags for url, title, type, and image. The url meta tag gets visited, even if it's the same address the inspector is already looking at.

Fortunately, the post inspector helps you suss out what's missing in some cases, but c'mon, man, how much effort should I spend helping a social media site figure out how to render a preview? Once you get it right, and to quote my 13 year old: "We have arrived, father... but at what cost?"

This is a mistake that many websites make, trying to block all robots, and the robots that serve their blog posts to users can't function anymore.