A primary difference between academic and non-academic texts involves audience, which also speaks to purpose.
An academic, nonfiction text will be based on research methods that can be replicated. It will place the guiding question within an academic context (generally, this should be a disinterested endeavor to answer an academic question) and use peer-reviewed and respected sources to lead to a conclusion. The reader can follow the steps in the argument and decide if the evidence and the conclusions properly align with the question and the research method. The point is to advance human understanding in the discipline. Academic texts tend to use jargon, which serves as a shortcut for other academics already well-versed in prior studies and concepts in the area. This can make these texts more challenging for novice readers but serves the academic community by eschewing explanations not needed by the target audience. (This would be the equivalent of a sports writer not explaining what RBI or MVP stand for when discussing baseball.)
A non-academic text will bring the reading level down considerably so that a reader without much experience in the subject can learn basic information. Digitally, hyperlinks may now direct readers to definitions or other studies used to buttress the current text. Often, these pieces are summaries rather than original research, so the methods used to derive conclusions will be harder to detect. These texts will progress more as an argument based on claims and evidence but without any signposts for a reader to validate data. They can be reliable sources of basic information if a good editor verifies the piece, but with internet sources, it can be far too easy to post unreliable information that has not been properly reviewed. Because the method of study is not as easy to verify, non-academic sources are also more likely to involve persuasion rather than argument, or to present spurious research studies without acknowledging legitimate counter-arguments.
The main similarity between academic and non-academic texts is subject matter. Both specialists and laypeople are often interested in the same topics: wars, such as World War I, World War II, and the Civil War; science and medical topics; big topics in history, such as the Renaissance; and biographies of famous people, to name a few.
Both academic and non-academic texts aim for accuracy, and both use research, though the research behind non-academic texts tends to be much lighter and to focus more heavily on secondary sources than that behind academic texts.
Both types of texts are also alike in trying to reach as wide an audience as possible, though the assumption is that a non-academic text will reach a broader readership. Both will almost always (always, in the case of academic texts) cite sources and include a bibliography of some sort. Both are indebted, almost all of the time, to an academic tradition of integrity, and both try to build a coherent argument, even if it is a very simple one.
Academic and non-academic texts can at times address the same subjects. For example, an article in a newspaper or magazine written for the general public (an example of a non-academic text) could address a subject such as global warming. An academic text could address the same subject, but it would be written for experts in the field and might contain specialized vocabulary and scientific data. In addition, academic texts have usually been reviewed by other scholars and found to meet high standards for research and integrity (in that the sources in the article are all cited and the authors have not appropriated other researchers' ideas as their own).
In addition, both academic and non-academic texts can be useful for researchers and students. For example, if you were trying to research data about global warming, you could read both non-academic texts in the form of newspaper and magazine articles and articles on the Internet, and you could also inform yourself about the subject by reading academic texts in specialized journals.
Finally, the authors of both academic and non-academic texts (at least those non-academic texts published for the public, such as magazine and newspaper articles) are required not to plagiarize. If they use other people's ideas or words, they need to cite the sources of their information.
It is much easier to say what academic and nonacademic texts do not have in common rather than their similarities, but I can say the following:
Both academic and nonacademic texts may be written with the goal to persuade, to entertain, or to inform. They differ in their approach to these goals, though, with academic texts relying far more on research and factual, verifiable material for their content. Nonacademic texts may also include research or verifiable material, but are less likely to include references to any source material, and may be published in a rather informal setting.
Academic and nonacademic texts are also typically written for a particular audience. While nonacademic texts are intended more for mass, public consumption than scholarly or academic texts, they may be targeted towards special interests or occupations in society.
When it comes to format, both academic and nonacademic texts may be found in print, periodical, and digital forms.