Why are links so important?

Bad company corrupts character. Links are much like referrals in the real world. The better people you hang with the more perceived validation you receive. When you started in business you probably did not know very many people but as you got more clients then people would refer business to you and you knew people you could refer out to. Links work the same way in the virtual world. 

If you get a link (referral) from a valid website like an .edu or .gov then Google does not need to find out if those organizations are legitimate. They are which means you are in there mind. The more valid companies within your sphere of influence will build better validation for search engine spiders. In the real world this takes time and a lot of effort. Expect the same thing in the virtual world but also expect the retun on investment. 

What happens when you go from 2 links to 250,000 overnight? Well you guessed it. The Google flag goes off and they say "You cannot build your business that fast so why would we believe you could do it virtually. This is a great way to get banned. Growing your online business is like growing a regular business. Slow and steady and you WILL win the race.