== A fundamental problem with the trackback protocol

In vague theory one answer to [[my problem with the modern web hiding
discussions SocialWebHidesDiscussions]] is for the modern web to support
the [[Trackback protocol http://en.wikipedia.org/wiki/Trackback]]. Except
that the Trackback protocol is (as far as I can tell) basically dead at
this point, killed by any number of things including a lot of spam.

When I was thinking about this recently, I realized a fundamental
problem with the whole Trackback protocol (besides [[this issue
TrackbackThought]]) and why it was almost immediately abused. To put
it simply, the problem with trackbacks is that they are not a means
for telling you when someone's linked to your web page; we already
have a perfectly good mechanism for that in the form of _Referer_
headers. Instead trackbacks were in practice a protocol for causing
links to appear on people's web pages. As the latter, they were always
destined to be basically an engraved invitation to spammers.

(Some people will say that _Referer_ only works if readers actually
follow the links from the other page to yours. The simple answer is for
the blog software or the author to deliberately do that (perhaps several
times and/or with a specific _User-Agent_) simply to get the information
into your logs.)

Now I will go flying off on wild speculation. As I understand it, not
all web hosting firms give you easy access to things like _Referer_ logs
(I have vague memories that cheap low-end web hosts are especially bad
about this). In the face of such a hosting environment, it's probably
an easier hack to add an entire protocol (which can be implemented in
your PHP code by you) than to try to argue your host into giving you log
access. And it's more likely to work reliably in that if your site is
working at all (and allows you to actually write stuff), it's probably
going to be recording trackbacks.

(This line of thought makes me wonder if anything else has been created
to get around the limitations of cheap web hosting. Arguably PHP itself
caught on because it was easy to host.)