Using websites like ezinearticles that allow comments to be added to the bottom of the articles can help in a number of ways as follows:

1. Traffic
2. SEO

There are most likely more but these are just to ways. What I do and also others is reply to articles that relate the subject of my websites and are new, old ones also help but if you get the new ones then your most likely going to get more traffic, if the article website like ezinearticles is a very busy and well read website.

When replying to the article make sure you have read the article and give a good comment also don’t add more than one link and make sure there is a good reason the link should be in there, remember that websites like ezinearticles check the comments before submitting them to the article, so the less spamming it looks the better for you and this will increase your chances and your traffic in return. One good point to remember don’t forget to add your main keywords within your anchor text else there will not be much off site SEO going on for you.