I know that kosher pickles really are inspected and approved by a rabi, so what is wrong with regular dills?
The Master answers:http://www.straightdope.com/classics/a1_351.html
I am enlightened.
As someone who both keeps kosher and loves pickles, I can tell you that there are pickles certified kosher and ok for Jews to eat that are not called “kosher dills.” And I’m fairly certain that not all pickles known as “kosher dills” are actually kosher according to Jewish law. I don’t think there’s are real correlation.
The speculation on Jewish.com (http://jewish.com/askarabbi/askarabbi/askr4341.htm) is that the pickles labeled “kosher dills” are pickled in the same style as the pickles that gained popularity in kosher delis. I can’t vouch for that, though it does make sense. But not all pickles that are kosher are Kosher Dill Pickles. I can certainly vouch for that.
A thousand pardons for feeling it necessary to add to the master’s answer. I will add that the possiblity of non-kosher ingredients, such as animal preservatives, in the brine IS what makes some pickles non-kosher under Jewish law, as Cecil said.
This reminds me of a story. Some years ago, I worked for an old and respected consulting firm. In fact, the first commecial consulting firm (from their PR department anyway).
We had a contract with a large pickle manufacturer who’s name rhymes with “Flasik.”
We designed a built the ultimate pickle machine. Cucumbers went ito a bin at one end. Each cucumber spilled into an optically-encoded slot on a huge conveyor belt which whisked it past a series of scanners which would determine it’s length, girth, curvature and bumpiness. These parameters were fed into an algorithm which determined what ultimate fate was in store, be it a bread-and-butter slice, a kosher wedge, a macerated relish bit, etc… As the cuke shot down the pipeline, it would be shunted toward its final destination via a series of secondary conveyor belts, laser-guided water cutting jets and assorted space-age widgets.
The beauty of this was, that after all of this, at the end of the process was an old lady in a hair net, whose job was to put the last pickle in the jar, so it could be labeled “Hand-Packed.”
According to pickle manufacturers, the reason they need the hair-netted grandma is because it’s very difficult to get a machine to squeeze the last pickle into the middle of the jar without disasterous results.
Whether that’s true or not, grandmas may be more cost-effective than pickle squeezing robots. (Please note the confluence of both 1) Band Name! and 2) Exciting glmipse into the future of prostitution.)
And grandmas like to eat pickles. Won’t someone please think of the grandmas? 
I am reminded of the old joke involving a pickle slicer.