Re: [Phpwiki-talk] Re: Another use for Google's 'rel='nofollow''?

[Reini U. <ru...@x-...>]

Charles Corrigan schrieb:
> On Thu, January 27, 2005 17:31, Charles Corrigan said:
> 
>>I just looked at the access log for my site and noticed
>>that google was indexing it. And it was trying every
>>possible link from every page!
>>
>>Would it make sense to add a "rel='nofollow'" to links
>>such as "edit text" where it makes no sense for a robot
>>to follow?
> 
> 
> When I wrote that, it was already 7 days after Reini had started putting
> the nofollow attribute onto some of the links! My only excuse (hah!) is
> that CVS and then the lists had problems last week.

Does it work now?

> Anyway, I took a look and found that the changes did not work for me - I
> did not spend any time trying to work out why.  I just put a couple of
> changes in that worked in my testing.
> 
> /lib/Theme.php
> 
> - line 1184 - 4 lines in Button->Button()
>            // Google honors this
>            if (in_array(strtolower($text),
> array('edit','create','diff','pdf'))
>                and !$request->_user->isAuthenticated())
>                $this->setAttr('rel', 'nofollow');
> replaced with
>            // Google honors this
>            $this->setAttr('rel', 'nofollow');
> 
> - line 1210 - 4 lines in ImageButton->ImageButton()
>            // Google honors this
>            if (in_array(strtolower($text),
> array('edit','create','diff','pdf'))
>                and !$GLOBALS['request']->_user->isAuthenticated())
>                $this->setAttr('rel', 'nofollow');
> replaced with
>            // Google honors this
>            $this->setAttr('rel', 'nofollow');
> 
> 
> OK, some justification is required. In my opinion
> 1 - it does not matter whether the user is authenticated or not, only that
> if the user is google or another search engine, we do not want them to
> follow these links

Of course we could check for a search engine user_agent, but a simple 
$user->_level check is much cheaper.
rel=nofollow could also be used in some special accessibility browser 
(speechmode, ...).

> 2 - while there are some of the action buttons that it would be good for
> google to follow (RecentChanges, BackLinks), most of them I would prefer
> it did not.

So we should explicitly allow RecentChanges, BackLinks and deny all 
others? This will cost about the same.

> The downside of my changes is that there will be an unconditional
> additional 15 characters per action link in the HTML sent to the client.

-- 
Reini Urban
http://xarch.tu-graz.ac.at/home/rurban/