dropping links with rel="follow"

As some sites automatically add rel="nofollow" to a link, have been experimenting what happens when I add rel="follow" to a link.

It seems to vary site by site, but the majority do not change it to rel="nofollow"

Have seen
rel="follow nofollow"
rel="nofollow follow"
etc

Question is, what happens in the above two examples.

is "follow nofollow" valid? will it be ignored, or be considered nofollow?

It is consider to be nofollow.

I my self is doing blog commenting for a long time and with in 2 months google has F**ked up every thing most of the sites are now no follow.

Thanks for quick reply, thought as much.