Invisible Click Tracking Using “Empty” UTF-8 Characters

Just to point out that hovering over the link shows URL-encoded codepoints, i.e. %u200B (in Firefox, for me, at least). I do think it's a better solution than the existing approach with GET parameters which does look clumsy.

Nitpick:<p>&gt; The idea is to use zero-width and space characters of UTF-8 such as U+200B, U+200C, U+200D<p>That must be Unicode, not UTF-8.

Isn&#x27;t this exploiting the same kind of Unicode ambiguity that allowed phishing sites to impersonate trusted domains by substituting certain latin characters with identical-looking cyrillic equivalents? I would expect this capability to last long in the wild.

Anyone have a suggestion of how this would be used in practice for uniquely identifying something?<p>So there are a certain number of non-width space characters. As far as I can find in the links in the OP, U+FEFF, U+180E, U+200B, U+200C, U+200D would make 5.<p>So we have at least 5 values to work with, which would make... 120 combinations if they&#x27;re ordered differently? Surely we would need more if we want to uniquely identify something such as a referral, or are there more non-width spaces?<p>I&#x27;m kind of dumb and bad at probability, also. You&#x27;re encouraged to correct my thoughts on this and show me the errors of my thinking.

i don&#x27;t see any variables in the url when i run the inspector.

So who would pay for a tool to make creating&#x2F;handling&#x2F;analyzing these links as easy as using UTM parameters?

There are only a few chars, so urls grow huge, once click count increases. JS is probably better

Post as many as character you want and it will work. Here:<p><a href="http://kaspars.net/blog/web-development/invisible-click-tracking?​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​" rel="nofollow">http:&#x2F;&#x2F;kaspars.net&#x2F;blog&#x2F;web-development&#x2F;invisible-click-trac...</a>

Does this also work in mail readers?

I actually like this. Assuming you agree there are non-creepy reasons to track clicks (not a given on HN) then this lets you keep your urls nice and clean when people just want to copy and paste them.<p>I imagine it might break in some scenarios (the url ends up with junk in it from bad unicode conversion) but it&#x27;s up to you to be permissive in the urls you accept.