Earlier quoted context omitted.
Harvard Extension School is an adult education program, like night classes. Your teachers may be Harvard faculty (but never were in the 7 classes I took there), and the other students are not Harvard undergrads. Also there is no application: they take anyone with a credit card. (There may be an application if you want to earn a degree rather than just take desultory classes; I don't know.) That's all not to say the c…
So what does "getting into Harvard" mean - getting into Harvard College? What about the rest of colleges besides Harvard College and Extension School?
However, it is but one of several schools that make up Harvard University, which include graduate schools like Graduate School of Arts and Sciences, and professional schools like Harvard Business School, Harvard Law School, and Harvard School of Medicine.
There is overlap between the different institutions at Harvard; the Faculty of Arts and Sciences teaches undergraduate classes at Harvard College, graduate classes at the Graduate School of Arts and Sciences, and performs research.
Harvard Extension School differs from many of the other schools in that it is not selective; anyone can simply pay to take a class. That means that merely attending Harvard Extension School confers considerably less prestige than attending Harvard College or one of the other schools at Harvard; all it means is that you paid for some courses.
Saying you "dropped out of Harvard" makes it sound like you were really brilliant and had a lot of promise but founding your own company held even more promise than finishing your degree. Saying that you dropped out of Harvard Extension just says that you took a few night classes and never really got around to finishing anything.
I took a few courses at Harvard Extension in high school. Some of them were really good, some of them not so much. A top notch school tends to offer a much more consistent program than Harvard Extension school. I've also attended another Ivy League school (group of very prestigious, fairly selective schools in the Northeastern US) as a full time student, as well as a flagship state school, and I can say that based on my personal experience, I'd rank Harvard Extension a little below the state school (which also had some really great classes and some mediocre classes), not up with the Ivy League school.
More info on all of the schools that make up Harvard University: http://www.harvard.edu/schools