The term "popular" includes a few types of publications including entertainment magazines, news magazines, special interest magazines, and journals of commentary and opinion.
Entertainment and Recreational Magazines
Entertainment is a perfectly good purpose, but these publications are not for any academic use.
Articles are very short and never cite sources.
Authors are usually staff writers,
Entertainment magazines include a lot of advertisements.
If in reading an entertainment magazine you come across an article on a topic you want to pursue academically, check scholarly journals and/or reputable news magazines for more substantial information.
Examples of entertainment magazines include People,O: The Oprah Magazine, Good Housekeeping, and Rolling Stone.
People
Magazines of Commentary and Opinion
These publications provide a forum for the discussion of social and political issues.
The intended audiences is the general educated public.
Some publications have a specific point of view, e.g. conservative or liberal.
Articles may be written by public figures, representatives of organizations, or professional authors.
Article length varies, with some publications having very short articles, others lengthier.
Most also include book reviews.
Examples of commentary and opinion are The Atlantic, The Nation,National Review,The New Republic, The Progressive, and The Weekly Standard.
Magazines of commentary and opinion may be appropriate sources for some college assignments.
The Atlantic
News Magazines and Newspapers
News magazines and newspapers keep the public up to date on current events.
Articles are written for the broad general public.
Most publications include both short and long articles.
Some publications, such as The New York Times, are known for publishing in-depth investigative articles.
These publications rarely give citations, but sources are often noted in the text.
Articles are usually written by journalists.
News publications usually include photographs and advertising.
Newspapers are also often known for their editorials and book/film/theater reviews.
Reputable news magazines and newspapers may be appropriate sources for some college assignments.
Time and The Economist are examples of news magazines.
The Economist
Special Interest Magazines
Special interest magazines target people who want to read about an avocation or other special interest.
The topics in these publications may often be pursued at the professional research level and written about in scholarly journals. However, special interest magazines target the non-scholar.
Special interest magazines may use specialized vocabulary and assume some prior knowledge of the topic.
These publications rarely include citations, but sources are often noted in the text.
Special interest magazines contain advertising and are heavily illustrated.
Some special interest magazines are published by non-profit organizations. Examples of these magazines are Audubon and Sierra.
Other special interest magazines include AARP The Magazine, Astronomy Magazine, Money, Psychology Today, ScientificAmerican, and Vegetarian Times.
Special interest publications may be appropriate sources for some college assignments.