I'm all in favor of promoting solar and raising awareness for renewable energy. It doesn't matter if it's with buttons, bumper stickers, social media (twitter, facebook etc.), web sites or search engine marketing (seo). The more the better.
But never forget that solar power is seen as a riskier than the alternative -- power supplied by the local utility. This perception of risk comes from the fact that solar is more complex, installation is not as simple, solar costs more, and most solar dealers/installers are smaller, unknown companies (at least compared to the local utility).
So don't expect people to seriously consider buying solar based on a promotional button, twitter or bumper stickers.
Think of it this way: If you had a serious heart condition and needed surgery, would you select a surgeon based on something you saw on a bumper sticker or read on Twitter? I know I wouldn't.
I would look at a surgeon's reputation, ask for recommendations from other doctors, determine which hospital the surgeon is affiliated with, investigate the surgeon's credentials and formal training, and definitely talk with patients who have had a similar prognosis.
Solar isn't a life or death proposition like heart surgery, but the trusted sources of information needed by buyers to reduce risk when making a high-risk decision do not include promotional materials developed by the vendor.
Promotional content does NOT help the customer lower their perception of risk in buying solar. And branding only works on cattle.
Marketing solar (which is higher risk) the same way that Coke markets soft drinks (little or no risk) is one of the reasons the solar industry has such a hard time breaking into mainstream markets.
Marketing High Risk Products
Solar's Main Competition