If I didn't have a heart I would have gone into advertising, specifically for branding. The topic is a long time interest of mine, so here's my amateur opinion with education on the branding world.
The success of a brand depends on synching an idea/product with one name. At this point in time, an encyclopedia is rapidly approaching Wikipedia instead of World Book or any other publication. Now, these are publications not generally identified with a brand, but a product name. "I'd check an encyclopedia like Encarta or World Book" and nowadays "Wikipedia". The concept of an encyclopedia has not been branded. Another example is in the American South: every carbonated soft drink is Coke. "Do you want a Coke?" "Sure, Sprite."
Wikipedia is on its way to take this over, just as "googling" exists. It will further overcome the nomenclature for index research. Now, how can we expand this into another name?
Simple answer: we can't.
Open Knowledge, Free Knowledge, Creative Commons, Gnu, Wikimedia, nothing holds a candle to replacing a verb with a noun. We google, we skype, we Wikipedia. Advancement of the Wikipedia brand is the only feasible option to expand Wikimedia coverage, as shown by almost every study both academically and journalistic relating to our products. If Wikipedia is tied into any coverage related to a sister project it will be read and understood. If not tied in, we get confusion.
The Wikipedia brand brings distrust but acceptance to any project stamped with it, and that is our key in the market. People just want to know, as emphasized by the American commercial where a guy is arguing on the phone about when "Whoop There It Is" came out and he is proved wrong by en.wp mobile. When someone just wants to check something, the name Wikipedia is ruling the roost. The Wikipedia name is the brand. How to boost other projects based on the name is to build all projects into recognition of the Wikipedia umbrella. Google is, so far, what does this.