Almost half a million people pre-ordered the model 3 so the brand definitely has some awareness and clout. Sure, those aren't assured buyers, but they are people willing to put down 1k for a car reservation. The amount of people who are still interested in Tesla beyond purchasing a car in the near future is some degree larger than that.

That sort of following and interest can help Solar get more well known, and not to mention further integration with Tesla can quicken drivers along to SolarCity products.

Not to mention, everyone I know has heard of Tesla. You must have interesting friends!