Robert_Charlton - 5:38 pm on Mar 13, 2009 (gmt 0) JohnMu Matt Cutts [edited by: Robert_Charlton at 5:40 pm (utc) on Mar. 13, 2009]
Prompted by this thread, Barry Schwartz discussed the syntax error question with Google's Matt Cutts and JohnMu. He reports their responses in this discussion at Search Engine Roundtable [seroundtable.com]. Their responses...
The microformat is explicitly defined as rel="nofollow". I would not count on other rel-attributes having the same effect, even if they look similar at first glance.
I'll have to check whether we flow PageRank through links specified with a space such as "no follow". You can bet that we'll run a test and consider adding support for it. We often add support for when webmasters appear to mess up their meta tags or robots.txt, but we think the intent is pretty clear. The idea is to help webmasters achieve their goals, not be nitpicky about syntax.
[edited by: Robert_Charlton at 5:40 pm (utc) on Mar. 13, 2009]