The way a domain was used in the past could potentially impact a domain owner, so researching any potential domain acquisition is important. Not only could prior usage put a domain owner at risk of losing his domain name due to a UDRP, but there could also be untold legal risk when acquiring a domain name, and also issues with it appearing in search engines.   All of these potential problems can cause much financial turmoil as well as take time to remedy and reconcile.
The first and probably the most obvious concern is prior TM infringement with a domain name that may have multiple meanings. If a domain name was previously parked, and the PPC links infringed on another company’s mark(s) where the domain name is also confusingly similar to that company’s marks, the company may have a legitimate complaint. If a new domain owner takes possession of the domain name, it doesn’t negate the issues that existed before. The complainant could cite prior use of the domain name, and the new owner’s claim of non-responsibility probably wouldn’t fly.   I think this is especially so in the case of three letter .com domain names, where there may be many companies whose trademarks could be infringed upon.
If a domain name was involved in spam or phishing emails, the new owner may be held accountable.   I am not an attorney, so I am not going to say what liability may exist, but from a public relations perspective, it could be detrimental. People may have posted their spam/phishing messages in forums or other websites, all linking back to the domain name. If the domain name gets developed into a website, it might be tough to be legitimized if enough questions were raised – forever linked in Google search results.
In addition to these issues, there are also spam blacklists that exist. If a domain name is put on the list, many mail servers may not accept incoming mail from certain domain names. While that may not be important for mini-sites or for parked domain names, if a business is built on that domain name, email access will be critical. A company may be able to appeal to the blacklists (like Spamhaus), but I don’t know how to handle that.
If a domain name was previously parked or if there were other major problems with it, Google and Yahoo may have banished the name from their listings. Upon changing ownership and/or building a new website on the domain name, it might not even appear in Google or Yahoo because of the domain name’s past history. There is a way to remedy this however, by filing a reconsideration request with Google or asking Yahoo to re-review the website. Neither of these will guarantee that your site will appear, but it’s a good start.
Research is key when buying a domain name. Archive.org offers a great tool to see what the website looked like at various points in time, allowing you to see the history of the site.   Domaintools also offers many valuable research tools to see the ownership history, blacklist history, screenshots, and some other useful tools. While you may think you are buying a domain name with a clean history – or one whose history will be cleared when you buy it, but it reality, it’s always buyer be ware.