Kewpie Mayonnaise

What's the deal with the popularity of Kewpie Mayonnaise? I don't use a lot of mayo, so I've never purchased it. I'm seeing it in a lot of lunches in the flickr group and I just noticed that my local Daiso is selling it. I'd kind of like to try it, but I don't like having huge bottles of anything sitting in my refrigerator, unused. Does it keep like regular mayonnaise?