rel="nofollow" attribute in a-Tags was initially proposed by google and was supported by MSN and Yahoo! The intention was to stem spam-links, that can largely occure in some webpages, especially blog comments. The famous blog engines founded that idea very cool and most of them are setting the nofollow attribute out of the box. WordPress does it by default too. But like many of good-mentioned ideas can lead to some not wanted problems.
Let's look closely on nofollow attribute and his purposes. If "nofollow" relation is set within a link, the searchengine (like google) should not consider this link in the Pagerank calculations.
But what is when all comment of one blogsystem are marked with "nofollow" by default. Does it mean, that all comment on your blog are spam, or irrelevant information? If so why enabling comments at all? Nofollow probably does not make really sense in comments or at least in all comment per default. Then comments that are deserve to be marked as "nofollow" are not really comments you wish to see on your page. They should be deleted by your spam-filter-plugin. So the is not really any need to have "nofollow" in comment links.
But many of famous blog use it per default.
No NoFollow intitiative
So should we consider nofollow attribute harmfull in any case and forever like No NoFollow intitiative1 do? Let's inspect their 11 Reasons agains nofollow:
- nofollow does not prevent comment spam - There are to meany points in this statment. At one side, of course "noflolow" do not prevent automatic spam. Further it can lead to fewer human-made spam (if someone sees that somebodys blog sets nofollows at default, he may not post sensless post, just to have link. Of course in this case, noffolow leads to the fact, that also wanted comments are in absence, be course authors becomme no "revard" for theyer commenting job.
- nofollow is confusingly named - i don't know, i think this is not a point.
- nofollow harms the connections between web sites - I agree with that, the default and not human evaluated nofollow - harms!
- nofollow is not useful for humans, just for search engines using PageRank or a similar technique - Yes, but where is the problem?
- nofollow could be used to shut web sites out - This is true! And it can be very powerfull. Imagine: all bloggers from now on will sets nofollows on the wikipedia links. Ok you will be never able arganize something like this, but if...! ;)
- nofollow discriminates legitimate users as spammers - That's true. And is one reaaly big problem!
- nofollow commentators earned attention - This can be true, as already mentioned at number 1.
- nofollow could be used to further discriminate weblogs - I think that says nothing.
- nofollow prevents the Web from being a web - That not precise, it contradics to the statement 4. I think web stays web, nofollow does only change the searchengines view of the web and that is something different!
- nofollow eliminates the dissemination of free speech - Oh yea! Say humane rights defenders from "NO nofollow party" ;) Why people always try to argue that way to get attention ? ;)
- nofollow was developed in privacy with only search engines companies taking part in the discussion - Yes it's true but also many of other beatifull, well accepted things. ;)
What i think
I my opinion we should be careful with "nofollow". Nofollow can be dangerous. No follow does not change the world in better way, and spam should be fighted before it reach web page. If spam is on page (in comment, forum-post, ..) it already to late, and nofollow do not handle it.
But the can be some usage for noFollow if can be handled by humans and not automatically. For example if someone buys adverting on your page. Or probably you cites someones page that you don't like, ant you don't wish this page gain from it - why not "nofollow"?
I am sure, future brings more relation-tags, to specify page relations more precisely. "Nofollow"- Tag may be not the perfect one, so use it careful or just don't touch it - disable it!