What causes sandbox filter?

This is an important question asked several times in forums, message boards and blogs. No one was able to give a definite answer for it. Even we had to struggle a bit to figure out what this sandbox is all about. Finally with our experiment using different strategies on about 15 sites we were able to find the cause of the sandbox filter. Our experiments prove that about 90% of theories circulating around in forums and other articles are wrong. Sandbox filter is caused purely by links and nothing else. It is just the abnormal growth of links in google algorithm's eyes which results in a site being placed in sandbox.

As we all know, internet is based solely on natural linking. Search engines and their ranking algorithms are the main cause for artificial linking. Now search engines like google woke up to the occasion and are combating link spam with sophisticated algorithms like the sandbox filter. Sandbox is a natural phenomenon affecting sites using any sort of SEO type methods to gain links. Next topic explains it. Sandbox filter relies on trust rank
to identify quality of links not PageRank as it used before.

Trust rank is a new algorithm active with google. The name trust rank is common for Google, Yahoo! and other search engines. So we can use the word trusted links. Trusted links are links which are hand edited for approval, algorithmically given maximum credit to vote for other sites like links from reputed sites, links from authority of the industry like the .gov sites etc. Google's new algorithm sees what type of trusted links a site has, especially if the site is new. If a site starts off with SEO type links than naturally gained trusted links, the site will be placed in sandbox for a period of up to 1 year or even more.