#3 - like the font, but the plus sign is giving it a "medical/health/fitness" connotation. Also, this particular green shade isn't giving a powerful image.
#2 - the sum sign within the circle is good idea, but not "web2.0". it's kind of something i would have used for an "offline" company. ours is going to be a universal online platform
#1 - i like the font. it's comparatively better amongst the 3, but still not the best. I'm expecting something extraordinary.
PS: dear design gurus, please don't mind if i'm too direct in expressing my dislikes. :)