what the different in do follow and no follow i think no any cos social bookmarking just send traffic to your site
if you use nofollow tag, when google read your link they cannot follow to the link, but if you dofolow, google can follow it until they find the site
with no follow link you cannot get PR juice but traffic is still there with do follow you get traffic and PR juice as well
In SEO point of view its better to submit in dofollow sites... But there is no harm in submitting to nofollow sites because it may help in providing more traffic.
Dofollow backlinks provide you both traffic and search engine ranking. Nofollow links only provide you traffic.
Do follow is pass everything without restrictions. No follow gives nothing much like SEO value, but still it record as a backlink and it can send you visitors.
Only different if it is linking toward you. If you use it no diferrence. But if you get a follow link that can give you PR and other benefits
Well, the basic difference between the Do follow and No follow is that you can get back links and relevant and good traffic from DO follow while you can't get back links from No follow except traffic...
I do agree with everything that was said, but it's important to mention, that you should not only build dofollow backlinks, but also nofollow ones. If you only get dofollow backlinks, Google will recognise that you are creating backlinks artificially and are therefore trying to manipulate them in a way. A natural link growth also contains nofollow links and therefore you should build them too, to make it look like people are naturally linking to your site, because they like it, not like you building them for manipulation.