Creative Commons Licenses

I am a graphic designer/web builder. I found some icons I would like to use in a web app. But I can’t for the life of me figure out their Creative Commons Share-Alike License.Which makes me feel really stupid, since I can’t even figure out the “plain English” version, let alone the Legalese version.

Specifically, I don’t understand the “Share-Alike” portion:

Now, does this mean that ANYTHING I make using these icons must have a Creative Commons License (i.e., I have to allow anyone to use my web app for free, assuming that they give proper attribution)? Or does it only mean that I can’t redistribute the icons themselves w/o adhering to such a license (i.e., I couldn’t copy them, post them on my site, and sell them for $125 a set)?