It is a filter created to discourage spam in google. What it does is not allow your site to rank for any competitive terms until you get out. This can be escaped if you build enough GOOD QUALITY links to your site.
At what point in the indexing process should you expect to be in or out of the sand box? Does the number of incoming links you have pointing into your site play a significant roll in its index profile? The reason I ask is I figure the key to gaining traffic and getting page rank is not justbased on the content of the site but also on the number of incoming or pointing link. If I had a site with a 0 google PR and was able to generate say 5-6 incoming links from sites rated 6,7,8 doe that play a significant role in the frequency of my sites index?
Links to your site do play a great role in indexing. When google crawls Site X and sees a link to your site it will follow it and begin crawling yours and probably index it. The more links to a site/pages the more chance it will get indexed. Even your links over all your pages don't send them all to your home page. If you can get some good backlinks you can get out of the sandbox or even skip it. The sandbox is not a set time so it will last as long as you wish. Also remember links from directories, links pages and recip links are being discredited and will not give you that much value so try and get links from real sites related to yours.
Because directories and forums are very low quality and don't give much value to you. Writing a few articles and submitting one per directory works though.
Xml sitemaps are for large sites to show google what are the important pages. Sites with less than500 pages or so don't need them. An html sitemap could help some on your site however. Just continue to build links with articles and you will get indexed. Read my article above if you haven;t yet.
So the key is good incoming links not necessarily recip links or directory links. Got that. I am building several sites in an effort to draw the links and traffic. I own 2 construction companies, each with there own sites. One has an alexa rank of 200K the other in the 300K range. I still have a google PR of 0. Both sites have on average 100 incoming links point to them. Mostly directories. I am currently working on a human edited high content directory and a construction advice site. All different domains unrelated companies. the directory has links that will point to all of the construction sites on each page. They pay for this privilge and that pay for the site development. The question is. If i have several 1000 links non recip pointing from the directory to the other 3 sites would that improve the potential page rank of the 3 costruction sites?
Interesting question. I googled the web and found this PDF. GooglePageRank.pdf Its a big pdf, but glance page 34 and 35, that discuss about your interlinking techniques. Before you read, let me clarify, I am not a math nerd.
None relevant links are greatly discredited. they still hold value depending on the value of the site and page. What you are referring to sounds alot like a link farm idea and I would discourage it. Try and write informational articles on construction giving tips and advice on building(depending on what construction type it is). These will bring links by themselves if written well and visitors will love them. Content is king....