1) For Getting Audience
If you are writing articles to spread your knowledge to a vast audience, the first thing you must check is that 'How much popular' is the article submission site.You could check it out by simply observing various 'Article Counts' and finding out the number of subscribers to that site.
2) For Getting Links
EzineArticles did allowed 'Dofollow' type links in the main body of article till a while ago ,but now they have restricted 'Dofollow' type links to only inside the 'Resource Box'.
Another problem that arises here is that most of the article submission site does not pass 'Resource Box' to their free web content subscribers. So your 'Dofollow' type links will remain bound inside the main article only.
3) To Get Web Traffic
Your writing skills is the factors that brings you web traffic through articles. You should do your writing brilliantly so as to drive traffic via links in the 'Main article Body’. You could give a small interesting description and exploit the readers interest to read the rest of the story via links.
You should also be careful that your article is something that people loves to read and is based on some trending topics. You could find what are the trending topics on web using 'Google Trends' and 'Twitter'.
4) Product Reviews
Writing reviews on new products also need excellent writing skills. The article should be interesting so that the reader could get an interest in buying that product.
These are the things that one must keep in mind before submitting your article online. Here is a list of free article submission sites. Happy Writing.