Lines for ice fishing

Since this great website has expanded now to include many areas where fishermen do wintertime ice fishing thru holes in frozen lakes, I have a question regarding fishing lines used in cold, wintertime fishing thru the ice. What's the difference between regular copolymer fishing lines, and ice fishing lines like the Micro Ice and Panfish Ice and others I've seen. Is there really a difference or is it just a marketing ploy to get us to buy more line in the wintertime? There are some light lines that I want to try on my ultralight outfits that are advertised as "ICE" lines. Can I use these lines in warmer water like during the Spring and summertime without any problems? Anyone?