I've seen a few people wondering how big the maps are in Planetside 2, with at least one comment along the lines of, the maps don't look that big because of the bases. Ignoring that, because I think the bases are probably twice as big as the original game, I found this image online whilst researching another MMO.
The image below is a stack of maps that show just how large many video game worlds are. With this comparison, now you can make your own determination as to how large Planetside's continents will be. I'm only posting the link since PSU's forums automatically resize an image.
http://cache.gawkerassets.com/assets...0d5a70c2c1.jpg