Brion Vibber wrote:
You may of course turn it off on your own wikis (as you may configure or recode them in any way). Unless we decide not to support the campaign, the option will ship on by default.
I strongly agree with Brion on this. It should ship on by default.
Whether or not *we* should use it is a tougher question. It is primarily of value to small blogs with small communities which are ripe targets for wikispam. For us, there is direct and indirect value in the fact that our links are human-chosen and _mean something_.
We help the world by reducing the cost of wikispam. We help the world by helping google and other search engines find websites that don't suck. It's a tradeoff.
There's an additional irony if you think about it. One "cost" of this campaign to google is if the ignore links of value, thus reducing the quality of their search results. If we add the nofollow attribute, we remove our collective wisdom from the google dataset. This might cause google to rethink the wisdom of paying attention to this tag.
The general ethical principle seems to be something like this:
A good webmaster will identify links that appear on his or her website which may be of low quality (because not validated by trusted parties) and hint to search engines accordingly. This means that by default, MediaWiki should ship with this feature turned on, because small wikis do have a problem in this area. But it also means that wikipedia itself probably should turn the feature off.
(This is not a decree or anything, just one voice in the discussion.)
--Jimbo