Google Jail

Did you ever heard of the "Google Jail". There are discussions about penalties that Google put on new sites to prevent them ranking high in the search results. This is essentailly a "jail" that google put new sites in. The period can be 3 to 6 months.
We don't have definite answer about whether the above is true or not, but it is true that new sites usually don't rank high in search result pages (even if they've been optimized for search engine ranking). So, may be google do have put some penalities on fresh new sites ? Anything one can do to minimize the penality? Below is a few tricks/tips:

build your new site on a sub-domain of an existing site. Since the main domain is there for a while, your new site will not be treated as brand new.
roll out your site as soon as you have enough content. You don't need to complete everything before go online. Roll out a few pages first and keep adding to your site content gradually. The theory behind is: the earlier you get jailed, the earlier you will be released.
Try not to target your pages for the hottest keywords. Those keywords have a lot of competition, with the extra penalty, a new sites is almost impossible to rank high.