#2, and second choice is the last one, with minor changes

#1 Doesn't fit in with the rest of Hubski's design, so I'd say no. Also, if this were to be miniaturized for the web, it may be cluttered and difficult to read. As a stand-alone art piece, though, it has merits.

#2 I really like this one, but instead of 4chan, I'd use reddit. I think this one would appeal instinctively to the widest number of people, and capitalizes on current social networking politics in a humorous way.

#3 I like, it's clear, vivid, well-designed. Wondering, however, what the average non-hubski-er would get out of it, if that is these sticker's intention

#4 Visually, it's nice. Doesn't use Hubski's name, and it seems more a non-specific illustration, which reduces its viability, and some people might not like that graphic (they prefer different styles), reducing its use.

#5 It's nicely done, but the designer in me is sensing something off about it. Also, this white lines in a sea of dark color can be difficult printing wise. The "stars" also seem random and I'm not sure what they refer to. It also doesn't share hubski's color scheme.

#6 Better visually. The logo, however, I don't see it reflecting hubski's actual logo. Also, the visuals in the background could be misinterpreted, misconstrued in a number of ways, and might present problems with printing it.

#7 Replace the logo with the hubski wheel we're all familiar with, and this would be my second choice. I really like "What can be learned?" it's a good tagline with a multiplicity of uses. However, let's say that image were to be printed on much smaller stickers. The small size of the text in the corner present problems when considering printing different sizes.