What exactly is an abstract? i understand that it ...

As long as you keep your writing to yourself and do not sell them, you should be safe. If you'd like to publish your writing in a newspaper or wherever, you should be licensed to do so. Contact the publisher to avoid trouble.

I think you are confusing an abstract with a summary. An abstract is a short piece that appears at the beginning of a thesis or a research study. It contains a short description of the problem under study, how the study was conducted and conclusions of the study. Therefore I think you are asking about publishing a summary and I don't think there is a problem since any publisher would be delighted with the publicity.

I can tell you what a scientific abtsract is: Basically, its an extract of the whole article/paper. 1-3 sentences about each section of the paper: Describing the background and state of art knowledge, the reason for the research /experiment conducted, method & tools, reasults and discussion. Many journals limit the length of the abstract and set their own slightly different rules. I suggest you ask lawyers about copywrite issues. 

If you're writing the abstract or summary for people in the United States, you might be interested in the U.S. Copyright Office's explanation of "fair use."

http://www.copyright.gov/fls/fl102.html