Is there anything to be careful of when aquiring expired related domains and pointing them to your main site, other than the domain having backlinks from 'bad neighborhoods'?? I've seen big sites like amazon do it - for example with ourhouse.com - if you type in ourhouse.com it simply takes you to amazons hardware section - so basically I assume that the practice is OK and not viewed as black hat in any way - any comments appreciated!
As long as you dont advertise the domain as haveing those particular backlinks at least I think it should be ok, if you know what i mean
It should be ok. Although if you are just going to the PR effect, I doubt it will be seen as a credible source by Google. Maybe if you added content to the domains it'd be a great boost in PR, which is what you are going for correct?
I think I read somewhere that Google have said that you can't be punished for bad sites linking to you. It makes sense as people would be able to do great damage to established sites just by linking to them from bad sites. Just don't link back. Be careful if you have an automated "Sites who link to me"-kinda widget. And if you are just looking for link-juice, you will probably get better results with a non-expired domain as Google tend to drop the juice if the domain drops.