With most foods that occur in nature, it can usually be assumed that there are definite health benefits involved. The nice thing about seaweed is that, because it grows in the ocean, seaweed has a higher concentration of mineral and nutrients than land-greens. I'm not sure I'd call it a Superfood, since I do not believe any such thing exists, but it definitely packs a punch if what you're looking for is calcium, iron, and/or protein.
Of course, you'll need to do your own research on what kind you want (either depending on which appeals to you most by taste/texture or what benefits you're most interested in) and how to properly prepare it. Rumors about the joys of seaweed consumption run from longevity and weight loss all the way up to miraculous cancer-dissolution, but as tempting as all that sounds please, PLEASE do your homework on this one. Seaweed can have suspiciously high levels of heavy metals and/or arsenic. Although this is rare, you should always be aware of where your shopping and what they're selling there.