Can you cite me examples (other than Facebook) where it was worth the hassle?
If by offshore you mean employ a 3rd party to handle the development of your startups tech product then you can consider the following scenarios:
You only have an idea, no validation from target market or MVP:
You know there's a market, you just need an MVP to start getting traction
You have already built and tested an MVP, achieved product-market fit and proof of traction and wish to scale:
Only AFTER it starts to make money and the business itself can pay for it. But BEFORE it achieves significant revenue - so that it will not be an expensive taxable event. EXAMPLE: I remember someone saying that Microsoft's costliest mistake, was not going offshore from the beginning. After they were making billions, going offshore would result in a huge tax bill. I don't know how they solved it. Moral to the story: Check with an attorney. I think she'll say, go offshore as soon as you start making money and pay the modest tax on the sale. BTW the company itself does not move. What happens is you set up an offshore entity and sell your IP to it. Then some of your US income will be paid to the offshore entity as royalties. A deductible expense here. Taxed at a much lower rate there, i.e. I think it's 1% in Ireland. I've had good results asking on Avvo.com - you can do that now for reference only - you still need to hire an attorney. But wait 'til your business has the income to pay for it. Good luck.
These are few big names developed initially by offshore teams.
Skype was developed essentially by an offshore team in Estonia
Digg’s first version was developed on a freelance website.
Socialmedian.com which successfully sold to Xing for $7.5 million was an offshore development.
Offshore development teams is a good option when you have limited budget. But finding a good offshore partner is really big problem, Most of the time offshoring fails in the terms of quality, specially when you are thousand mile away form your team. but every problem has a solution. We have a bullet proof solution for it. You will always high quality products, lower price and in time deliver.
Here is a good read about the pros and cons of a startup going offshore:
Offshoring for startups - does it make sense?