Here are a few of the issues you need to consider if you're repurposing marketing content created by other individuals for their own organizations:
Paraphrasing or Plagiarism?
Paraphrasing another entity's content isn't a shady practice as such, but participating in blatant plagiarism is. If the original author notices, you might be slapped with an order to take down the offending item -- and if Google notices, your company may sink in the search rankings. What's the difference between paraphrasing and plagiarism? It really comes down to how much of the original verbiage you use. If you must paraphrase, you must take the time and effort to completely rewrite the passage in question (by which point you might as well have created your own original content). Any word-for-word sections need to be placed in quotes or least attributed to their source.
Unique or More of the Same?
Your paraphrased piece may be as brilliantly stated as the original, or even more so -- but it won't be different in the ways that matter. If you're simply parroting what other industry experts had to say on the subject before you arrived on the scene, you won't make much impact in the sea of similar content. The right keywords might make your article or web page pop up in front of your target audience, but if the content surrounding them is nothing your prospects haven't read before elsewhere, don't expect to close any sales. Where's the original spin, the fresh approach? What's the "you factor?" Are you a thought leader -- or a thought follower?
Targeted or Generic?
A piece of marketing content originally created for one audience may hold little relevance for yours. If the piece originally referred to particular geographic areas or other details that appealed to their crowd, you'll have to take those out unless that author just happens to have the exact same target market as you. What's left is bland, generic text that doesn't clearly target anybody. Whatever the source of your material, you must always spin it so that it pertains directly to your clientele -- which usually means creating a big chunk of it entirely on your own.
As you can see, there's little to be gained by "flipping" existing materials from other organizations once you have to do all the extra work to make it yours -- especially when you could outsource your original writing tasks to a freelance marketing copywriter. True content optimization includes originality and creativity alongside the nuts and bolts of keyword placement, winning new customers as well as higher rankings. SEO stands for search engine optimization, not "search engines only!"