There is a lot of confusion, controversy, and questions surrounding the terms self-publishing, vanity press, print-on-demand, etc. As you decide the best publishing path for you, let’s clarify some misconceptions some may have propagated.
1. MYTH: Whoever owns the ISBN owns the rights.
FACT: This used to be true. Nowadays, it is no longer true. Good self-publishing options assign the ISBN for the authors’ convenience, but still allow authors to keep 100% of the rights to their books. Be sure to check the contract.
2. MYTH: Independent self-publishing is different from publishing with an established organization because that publisher owns the ISBN.
FACT: It is true that the ISBN identifies the publisher of record. With reputable options, authors can supply their own ISBN as an option. Of course, if an author prefers the publisher to assign an ISBN for them, that should be an option too. And that’s what self-publishing is about – author choice and author control.
3. MYTH: New York publishers promote and market all their books.
FACT: New York publishers usually devote the lion’s share of their marketing budget to the top 1% (Harry Potter, for example) of the books they publish. The other books published during that season are victims of the sliced marketing budget. The majority of traditionally published authors are referred to as “mid-listeres” and don’t get much support from their publisher at all.
4.MYTH: Printing a book with an off-set printer is the same as self-publishing it.
FACT: Printing a book is one facet of publication. Before a book can be printed, it needs to be designed. Then it needs to be printed. Then it needs wholesale distribution through Ingram and availability online with retailers like Amazon and Barnes & Noble. Then it needs fulfillment of orders and invoicing.
Printing a book with an offset printer accomplishes one of those steps. Publishing a book with a leading self-publishing option accomplishes all of them. Almost anyone can “print” a book, but what about all the other stuff that is required?
Self Publishing Advisor 
What if you want to use “offset” instead?
Jack – I’m assuming you’re referring to my usage, or spelling of that term. You’re right, the most common spelling is ‘offset’.