|Authors are staff writers or journalists.|
|Publishers are corporations, working for profit.|
|Sources are not usually cited.|
|Specific format is not followed.|
|Audience is the general public.|
There's actually more to this than ads or no ads/ references or no references. There are various sorts of "peer review." Also some folks would decide whether an article is valuable or not simply based on the reputation of the journal where it is published. One controversial measure of that is journal "impact factor." Here are some links in case you would like to explore these issues further.