If Facebook were starting today would it be a better strategy to sign-up one college at a time or sign-up collages across the country?

Think big. Start small.

You should always think of the bigger picture (i.e. Facebook for everyone in the world), because you want to make sure that you enable yourself to grow towards that point. Using Steve Jobs' analogy, it's about anticipating where the dots will be. Or as Wayne Gretzky puts it: skate to where you expect the puck will be, not where it is at the moment. Having this bigger vision in mind, will help you move forward.

That said, always start small. If you can make your product or service valuable for a small group of people (that are also representative of a bigger population), you can definitely figure out ways to reach those people. The initial challenge though is to make those first 10 / 100 / 1000 people really use your product or service (and preferably pay for it).

IMHO more often start ups fail because they haven't built something useful for even a small segment of people. So design for one person first, then one college, then scale.

Facebook today = Instagram.

Regardless of the constrained market (Colleges, Mobile, Format Type (Ex: Video) you focus on, you need to have it and create a great social experience.

The truth is, the only thing that will disrupt Facebook will either be a Photo or Messaging product, more likely photos (since their language is universal)

So maybe not colleges, but maybe photo site w/ a focus (ex: Pinterest), or format (ex: Vine, Cinemagram).

Everywhere we look, there are new social media channels popping up. While Facebook is one of the oldest in the space, it still has more users than any other social network today. Even though Facebook’s famed algorithm shift of 2018 caused concern for the future of organic reach for colleges, it strategically drives engagement today. From an inbound marketing standpoint, the channel can help your school or district reach both current and prospective families at every stage of your funnel.
Final site’s Social Media Marketer Darrian McClellan helps clarify the difference between a boosted post and Facebook ad. " "Facebook ads offer a lot more to advertisers than boosted posts do including more ad objective and optimization options, more customized targeting options, detailed placement options, and more creative control allowing you to optimize for various platforms and test different ad copies for performance,” said Darrian. This can be great brand recognition for your school as individual’s check-in on campus or at an event you are having. Colleges may see this a lot from members of their college community.
It also becomes part of their Facebook page. With the average time spent on Facebook lasting 38 minutes per day , knowing how to make a good impression, engage with a user, and have the right content in front of them at the right time will help you make the most of the platform. Not only do you want to prospect new families, but you also want to engage with current families, effectively reach alumni, and nurture your followers with strategic content. Facebook favours user content over brand content, which means users are seeing more content from their friends and family than from businesses. A successful Facebook strategy will come down to how well you interact with your followers on your school’s page. Social media platform algorithms go through a similar decision-making process in the blink of an eye, taking content and sifting through it before deciding what to convey to consumers. Similarly, once Facebook sees that an individual often engages with your content, you will be more likely to show up higher on their news feeds when you post in the future.
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath