About five months before we modified our website structure and left some pages unlinked with any other page in the website, means these pages are not reachable from any page of this website.
Now I am finding that these unlinked pages are ranking on the first page of yahoo and second page in Google for very competitive keywords.
I am thinking, Google and Yahoo gives more value to a page which has less linking in the website. Search Engine thinks that these types of page are low reachable to the visitors visiting on the site so SE gives more value for ranking and makes them reachable in SERPs.
Please share with me if any one is also observed this effect.