When you are dealing with the SharePoint Search functionality and you do not the content crawled for few sites, you can not figure out where the problem is? Probably, you get some generic error on crawl log like “the SharePoint item being crawled returned an error when attempting to download the item”
One of the reason that I faced is “Search Core Web part. If your page is containing the Search Core Web part, SharePoint 2010 crawler will stop to crawl the content from that point. So, if you are using Search Core Web part on your home page, that entire site will not be crawled.
Solution:
Go to Search crawl log, and exclude that page from crawl, automatically, crawl exclude rule will be created. Now, onwards, your site content will start to be crawled.
In fact this problem has been taken care in cumulative updates.
Enjoy!
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