Lot of times you might get an offer to get a link back from a website or a blog and it can be a wise decision to have a link in an article rather than on footer. It is obvious that a link back from an article looks a lot natural then the one in footer. Links in footer usually raise a flag towards being paid links. It need not necessarily be a paid link and there is no way to verify it and hence having a link back from an article is always safer.
In the video below, Matt Cutts explains how links in footer are treated by Google.