I heard on this forum that Google will de-index pages that do not contain intenal links. (orphan pages) I have seen this happen with some pages I made. Tey appear with good rankings for about 2 days then disappear completley. Can anyone confirm this?
I have no idea.. and I'd like to know as well.. may be you can use robots.txt to tell spiders to crawl those pages..
No, they don't. They'll drop the pages if your site doesn't have enough backlinks (to the page, or your site itself for that matter). If your site doesn't have a lot of authoritive links (from blogs, news posts, etc), then your pages may drop from left to right. it's all about backlinks really.
A page should eventually get dropped if it has no links, internal or external, but certainly not in 2 days. It can take months, possibly even years.
Crawler bots can find pages that have no backlinks or internal links thats their job, when it comes to indexing them its another story.
You can have 0 internal links, but if their is a backlink it would still be indexed. I'm sure they also index pages with no backlinks or internal links, this is the nature of how a crawler bot works and indexes websites.
robots.txt is for telling what NOT to crawl for telling what to crawl are sitemaps (or just internal linking of course)
Sitemaps are a structure of your site, it doesn't mean it will get crawled & indexed if displayed in the sitemap.
No, they don't. At least not in all cases. Have really old pages that are still indexed but have no internal links pointing to them and no external backlinks registered by google either. They even rank well because of their age and the Home page PR (6+).
My experience shows that every time you create a new page it should have some internal links created -- you can take a few days to do this. It allows search engines to find this page and even visitors can find these pages and hopefully link to them. A page that is not linked internally or externally is typically dropped from the index.