Do you think forum posting as a link building method still works?

The short answer is "yes."  If it did not work there would not be so many online forums on a huge diversity of topics.  They would never have survived for as long and as strong as they have since internet marketing became a viable income-producing option.

However, just posting on a forum does not insure the success of an online business or guarantee that that business is profitable.  The success of most if not all onlines businesses begins with the building of a list of subscribers and prospects.  And they must be courted in such a way that they come to know, like and trust you - the internet marketer.

How do you build that relationship?  Unfortunately, it takes time, patience. And a lot of effort.  Since most if not all of your online customers only know you from what they see of you online, your number one technique to building that relationship and letting your prospects and customers get to know you, like you, and trust you is through a sequence of emails which you send them on a regular basis.  These emails should include information about you, questions about what they want from you, free advice, perhaps an occasional free report or ebook, and only periodically a sales pitch.

To get back to the success of forum marketing, posting does work and it helps to build the initial list.  But as earlier explained, that technique is only the beginning of a successful business.

Yup! And you can increase their credibility by participating rightfully in the forums gain some knowledge share some do not just post spam on the users but be a goof person you will not only get traffic but also develop a good will which will help you to make new connections to enhance your business

Yes it still works effectively.

Yes. But only if you use it the right way. You should post your links in your signature.  Be wrong  and the forum will ban you.
Good pif you know what it is; if not see:
Example of a signature-

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@hcc_hhcn

Yes, Forum posting as link building method is still works whether the link is no follow. Most of the search engine like yahoo count both do follow and no follow link for website ranking.

If works to get links but those links may not count for much and you stand the chance of upsetting lots of forum users!

It is far better to get involved in a community, add value and gain links are traffic that way.