The nofollow attribute was introduced by Google to cope with the problem of spam links, for example comment spam in blogs. Links in comments should be marked as nofollow, thus won’t count for Google’s rating and thus would be worthless for the spammer. That was the idea.
But it might backfire for Google. Nowadays you can find the nofollow attribute not only in blog comments, but also social networks, forum postings and in Wikipedia articles. (It’s ironic: With Web 2.0 finally everybody could have his say – Too bad that it doesn’t count any more.) And with the spammers focusing on the sites that don’t use nofollow yet, these sites are likely to use it, too, soon.
So what’s the consequence?
By effectively abolishing the opinions of the small users only the website owners and journalists remain. Most website owners have their very own ideas about links: Their own products & services. And considering the journalists an interesting trend has evolved: Whenever they want to spice up their text with a few links for credibility, they link to Wikipedia. That’s easy and safe because they don’t have to check their sources for spam, fraud, etc.
Less diversity and less competition probably. The big fishes in the pond are bound to be the winners under these conditions. And Google is going to loose, too, because they’re missing the small, upcoming sites and trends. And just linking to Wikipedia instead.