Not bad. Digg is a premium word, you maybe can get away with it. Example like name.com they can't sue you if you have NameBoard.com Should be mid $xx to low $xxx according to user.
Yes, but name is a generic word and is harder to enforce copyright onto. Digg is not a generic English dictionary word, so therefore it's more of a copyright issue. Not worth the risk. I wouldn't even purchase this for the registration fee to be honest.
Emm..well IMHO it looks like a generic word Digg ~ means digging stuff Put a site like a black board and digg stuffs interesting. Get constant traffic from Stumbleupon and Digg for the stuff. Digg.com would be proud of having their name to your site soon
Correction my friend. Digg is a trademark as in Digg.com. Digging isn't a trademark. Digg and Digging mean two different things. In a court it would never hold up you meant Digging.