Nofollow links do not carry any link juice so therefore not influence SERPs. However it's still good practice to build Nofollow links as it will give you a more natural looking backlink profile.
I think nofollow links help a little bit. They basically help a website to look more natural, so I think that is the reason why they are useful.
I think they do help, not as much as a real dofollow link. I have seen sites with just a craigslist nofollow links and with no other links rank decently.
Nofollow links are not so much benefit for SERP It is natural looking back links but it is not count in Outbound Links.
No Follow links helps you to drive traffic to your site but not provided the link juice to your site.
Yes, Google recognises nofollow links and can pass trust vote so they definitely help in improving SERP.
Google follow Dofollow links which helps in indexing the page and increase search engine rankings. If you add link of your site in some high ranking websites, blogs, article directories and forums which consist Nofollow links..If your links are there, then visitors may visit your wbsite..It can drive free traffic to your website.
Yes, definitely. No follow links are useful for improving traffic on website. So it also effective for SERP.