They can be a really bad idea. Branch campuses, set up by universities outside their home countries, are blighted by myriad pitfalls.
They can fail to deliver the expected student experience, lacking the quantity or quality of scholars or the facilities of a home campus, leaving students feeling short-changed.
They can fail to attract the same calibre of students as at home, resulting in a lowering of degree standards and reputational damage.
They can impose inferior working terms and conditions on staff. They can cost an awful lot of time and money while bringing negligible financial returns. They can also simply fail - forced into a humiliating closure that damages a brand in the eyes of the global audience that was supposed to be impressed.
Then there are the cultural problems. How can a university committed to academic freedom operate in a country intolerant of political dissent? How can it work with a regime that disregards human rights? How can it post staff to places that do not tolerate homosexuality or discriminate against women?
In The Great Brain Race, Ben Wildavsky highlights other difficulties. He recounts the tale of a US professor teaching in Qatar who was the subject of a complaint from a female student: apparently his hand had brushed hers while he reached for a computer mouse. He was reprimanded for sexual harassment.
It's no wonder that many vice-chancellors reject the branch campus model and that many academics resist the lure of teaching abroad. There are serious risks and barriers involved, but there is also great opportunity. If a university has the patience and drive to get its model right, commercial possibilities abound.
As outlined in our cover story this week, it is a straightforward matter of supply and demand. Many developing countries have growing university-age populations, expanding middle classes, insufficient higher education capacity and a willingness to invest in overseas providers. Such countries present the chance to build long-term relationships, forge research partnerships, develop international alumni networks and burnish global brands.
But there is also an altogether more high-minded reason to embrace branch campuses - the desire to build a better world. Or as Christine Ennew, pro vice-chancellor for internationalisation at the University of Nottingham, put it to me, the chance to "promote great intercultural understanding by bringing together a genuinely international community who benefit from sustained exposure to each other's values and perspectives". Nottingham's campus in China is certainly not about short-term financial gain - indeed, any surplus is kept inside the host country.
Overseas arms do sometimes require Western universities to operate within deeply uncomfortable local cultural and legal constraints. But the accommodation and learning should not be all one way. Branch campuses can, slowly but surely, introduce host nations to new and different ways of seeing things.
In Wildavsky's book, one of the world's leading advocates of the overseas venture, New York University president John Sexton, describes the "challenge of the century": "How do we create a world where we don't look at things through a single window, but embrace all the ways of looking?"
One answer is the branch campus.