The sandbox is a crude explanation given by those semi skilled in SEO to explain various factors in the google algorithm that affect and slow down ranking.
You really want to look up temporal link analysis.
http://darksat.x47.net/topic/83.0.html&
http://techunix.technion.ac.il/~uriw/Temporal_link_analysis.pdfEg your links gain power over time and google watches out for sudden amounts of links that look like they have come from nowwhere.
This prevents huge amounts of artificial link building (unless you get creative with PR)
