You seem to be under a collection of interesting misapprehensions...

1. Google does warn in various ways when it detects possible badness. As it should.

2. We don't gate ALL links through such warnings. This can be verified by going to your news feed and clicking just about anything.

3. This is about a specific issue with notifications generated from comment widgets (a very common spam vector).

4. Detecting all badness via the domain name at "write-time" is not a sufficient solution to the malicious link problem.

5. Whatever that was, it wasn't reductio ad absurdum.

I have a problem with the way Facebook allows me to share links. Even by using your 'advanced' login security measures, I have been required to fill in CAPTCHAs hundreds of times for legitimate links. For instance, why is a link to an imgur JPEG file considered possible spam? Do you not whitelist domains? And isn't the repeated use of CAPTCHAs generally an abuse of the actual purpose of a CAPTCHA?

Additionally, Facebook has disallowed me from posting specific legitimate links. You've failed as a communication medium when you censor links. There was no indication that anything was wrong with these links that I shared with friends. There's no excuse for this practice.

Yet, at the same time, you allow seriously terrible practices on your own site, such as pages which require users to click on fake button images to do actions. It makes absolutely no sense how you are "policing" the integrity of your own site and the linking to other parts of the greater web.

>4. Detecting all badness via the domain name at "write-time" is not a sufficient solution to the malicious link problem.

Doesn't Google has this problem too, that detecting badness at the "indexing time" is not a sufficient solution? The content of a site may change between their checks. No pop-ups are shown in between indexing times nevertheless.

With your abuse reporting volume, you should be able to almost instantly detect statistically significant malicious links, and remove them from your news feeds, should the content change to malicious after "write-time".

I can't believe I'm posting something that might be taken as defending Facebook but...

If a site appears to contain malicious content at time X but not at time Y than I would PREFER to be notified that it is a dubious site until the site has earned back trust in some way. Continuing to warn users about a site that historically contained badness seems to me to be a FEATURE.

That's actually exactly Google's solution: they give you a set of reports and an indication of when the malware or malicious link was last detected on the site.

But I don't think that's the issue here. That facebook warning does not, as far as I know, get generated from a positive malware/spam/badness metric. It's just thrown up as a default action when someone links to an unblessed site on the web. That's what the poster doesn't like: it goes against the whole idea of hyperlinking.

But as lbrandy mentioned, this is in one rare case and appears to be the result of a bug. If this happened when most links were clicked leaving Facebook, you can rest assured that all publishers would be up in arms.

Hopefully it's a bug. But I see it routinely. It's definitely not a "rare case" by any metric I can think of.

Google scans for malicious sites as well. The difference is of course, that on FB people share links whereas Google can just decide not to include a link in the results and the user will never know.

If they had a limited objective of stopping malicious sites like Google does, they could reject the malicious domains at the moment they are attempted to be posted, instead of scaring users from leaving facebook.com each time they try to navigate away.

I happen to run a well known service, and we encountered the malicious links problem. It has never even crossed our mind to display those pop-ups, instead we stop malicious links from being posted after a domain is reported or detected otherwise.

Google has been criticized about banning less websites than they should - their preference is clearly towards false negatives, whereas Facebook's is clearly towards false positives.

google doesn't seem to have a problem with accounts being compromised from visiting malicious sites. I do like the incentive razor you've applied, but i think there is a simpler explanation in this case.