Comments Posting on Forums and Blogs

[Yi Song]

Hi,

Can anyone tell me how important is comment posting on forums and blogs. Is this technique really helps in earning backlinks for the site.

Should I go for it or leave it to save the valuable time.

And to earn the valuable backlinks should it be posted on the blogs and forums related to the subject of my own site or they can posted on any blogs and forums of the subject of my interest.

Thanks and Regards
Yi Song