Re: Bad Neighborhood
A bad neighborhood is loosely any website that violates a search engines terms of service in some way. It is a very broad topic but for the purpose of link building lets put together some guidelines (These are not concrete and fall under the "just to be safe" category)
Do not link to websites that do not have their index page or links pages cached. To check this copy the URL and type cache:www.domain.com/page.html into the google search bar
Do no link to websites that link excessively to off topic content. If they have links pages that link to viagra, casinos, flower shops etc, then they are in danger of being labelled FFA I (Free for all) sites and can get a penalty.
Do not link to sites that have thousands of inbound links from completely irrelevant sites - For instance if a realtor site were to buy irrelevant sitewides from say phpfreaks.com or something they could get a penalty for trying to artificially inflate their PR and backlinks. (This happened to this site so I am very familiar with this kind of penalty)
Finally just ask yourself "if this person asked me nicely for a link exchange and PR and backlinks didnt exist would I still consider it?" if the answer is yes and they dont fall under the above provisions then you are pretty safe.
Hope that helps
Starting LEC 7 soon but it won't be called LEC 7 - LEC 2012 coming soon!