actually, there are adsense on wp.com blogs. the difference is that those ads are not placed by the bloggers but wp.com itself. some wp.com have ads on them, if you view the blogs while logged out and through a google search. if you???re logged in you won???t see it.
that???s how wp.com keeps it free.
one of our great and informed commenter has just confirmed that wordpress.com does somehow profit one way or another. I just hope wordpress.com doesnt overdo it.
Wordpress.com is great so far. ....

