This is John Reinan’s weekly marketing column for MinnPost.com.

You know the phrase “caveat emptor:” Let the buyer beware. There’s another bit of Latin that people should acquaint themselves with: “caveat lector,” or let the reader beware.

Never has there been so much information available to the public. And never has so much of it come from people with an axe to grind, either politically or commercially.

Anyone over the age of 30 grew up in an era in which media choices were relatively limited. The mainstream media were conscious of their role as an information source for the broad public, and generally made a good-faith effort to be as objective in their news reporting as possible. (No, they weren’t perfect, but I’m not here to debate that.) Meanwhile, there was a clear distinction between news and advertising.

Today, information sources have exploded, and many of the most successful ones have a definite point of view. There’s the Daily Kos and the Huffington Post on the left, Townhall and Fox News on the right. The general-interest outlets that thrived on serving the broad public are the ones struggling to gain traction in today’s marketplace of ideas.

At the same time that partisan news sources are thriving, commercial entities are breaking down the wall that used to exist between news and advertising. Sponsored content is more common than ever, both on the Web and even in print media that used to disdain such things. For example, several Gannett newspapers in New Jersey have regularly published stories written by an employee of the NHL’s New Jersey Devils. And they didn’t always make clear his relationship to the team.

Here in the Twin Cities, Hopkins-based ARAnet has built a successful business providing content that offers useful information to readers – and also gives a boost to businesses that have paid to be mentioned in the articles. These articles have run in the Star Tribune and many other traditional mainstream media. I wrote about this previously for MinnPost.

While ARAnet’s sponsored articles provide credible information, the Internet also has spawned a crop of websites that pose as real news sources but offer nothing more than unsubstantiated marketing claims.

In addition, well-funded interest groups now have the means to quickly create websites that promote a particular point of view on issues of the day – and it’s usually impossible for a casual observer to discern who’s behind the effort.

In many ways, these developments are a throwback to the early days of the republic, when media outlets (usually newspapers) were created by partisans explicitly for partisan purposes. There’s a reason why so many newspapers have “Democrat” or “Republican” in their names. Readers knew that each publication had a point of view, and took that into account. It was only in the last 75 years or so that an increasingly educated, professional class of journalists adopted the mantra of objectivity.

It may be that we’re living in a Golden Age of media, when any kind of writing, recording or video is instantly available to anyone, free of charge, any time of the day or night. Viewpoints that previously were shut out of the cautious, middle-of-the-road mainstream media now can flower. There’s a lot to be said for that.

Just remember that many of the people bringing you this Golden Age are also hoping to enlist you – either in a cause or a transaction.

Caveat lector.