Hi Joanna
Great work! You give some reason why to take action, you accurately explain what the action is about and give some background on the organization.
Comments:
First and second paragraph can be shortened and combined. Just give enough reason to want to act then make a simple statement about the environment being threatened. People already know it, so very short is good.
Combine paragraphs three and four. Just introduce Bill and what he's doing.
Shorten the rest of the call to action. I'd give less background, because if people want more info they can always go to the 350.org website to read more (provide link at bottom of page).
I'd get more direct about your call to action. You can let them discover the other campaigns by writing in their link at the bottom: "For more information and to view other campaigns visit
www.350.org." But if you're trying to create a campaign I'd word the pitch in the final paragraph something like: "Join our campaign to take public transit 350 days..." and just leave it at that. That way they know what to do in very clear terms.
Check out
www.avaaz.org and read
http://www.netaction.org/training/part2a.html for ideas regarding online activist campaigns and how to write for them.