Now, before I start on this topic, I would like to tell everyone that these are my own opinions. I do not own Google and I do not know their algorithms, so let us keep the hate mails to a minimum.

Contrary to popular belief, backlinking speed does not really get you banned by search engines. Some people are a little too paranoid about their speed of adding backlinks. They ask whether adding more than 30 links a day will get them banned from Google. It wont. Not unless you do something really stupid.
Allow me to elaborate. When I started internet marketing, I would keep a note of how many links I put up for my website and made sure that the number per day never exceeded 20. Why? Because someone told me to go easy on the links or I would be penalized.
Now coming to think of it, this never made any sense. Let us look at the real-life scenarios. How many links do you think gets everyday? 20? I doubt it. A few hundred? Nope! gets over 10,000 links a day, I can bet you that! And even then it does not get banned from Google. This goes to explain that as long as you at least try to make the backlinks look natural, no matter how many you add, you will not get banned.
But let`s not start cracking up on the backlinks like a banshee. Do not get links from FFA or link farms in hopes of ranking high in 2 days for a competitive term. If you get links from FFA or link farms, you will most certainly get banned. I am talking about normal, legit link building techniques.
To put everything in perspective, I contracted a third-party service to give me 10,000 links over a period of 2 days. The website I have is only 3 months old currently. And it gets only 20 links on average per day.
But did getting 10,000 links over 2 days ban me from Google? Nope! Which leads me to believe that no matter how quickly you build legit links (or links that at least seem legit), you cannot get banned.
So folks, stop worrying about whether Google will banned you when you place your 21st link for the day. Nothing like that ever happens. If you are using black-hat techniques to get quick rankings, you might get into a problem.