I had hundreds of pages indexed in google but instantly have got them reduced to just 1. No link sales , no spam. My site is a bit new. Does this happen a lot ?
Is the sitemap okay or there are errors in it? Have you built links too quickly? Are you using a dropped domain? For a new site, some pages might get indexed but 100s to 1 is weird. I guess something is wrong. Check the site again.
yes this is normal but remember, if youre a new site, lauching more than 20 pages a day may send a wrong signal to google so dont rush and rebuild submit your sitemap to google verify your site to google do this by the webmaster tools
There are a thousand answers to this. Also check what outbound links you have. Google isn't very good at telling paid links from non paid.
This happens quite often, especially with new sites. I find that this happens more with MSN though, so it is a bit strange.
Check it probably like keyword stuffing and google assume it is spamming. Do not rush to launch pages. A new site with hundeds indexed seems to be not natural.