I've been involved with buy-outs like this - they are relatively common. One approach that worked out well was to create a "welcome page" on the the existing site for visitors from the newly acquired business. Then the 301 from the purchased site goes to that page. The relevance of the redirect target is made clear to Google, plus the visitors have a very smooth experience.

It might also help to set up Webmaster Tools for the domains you bought and use Google's Change of Address form in there.

So, when the new site is 301d, lets say to example.com/welcome.html it would pass the relevance and my home page would rank for those kewyords? good i shall try that and use webmaster tools to indicate google. Thanks :)

This sounds like it could be open to abuse and fairly obvious.

Sure, people do try to abuse 301s by buying up other domains. Google has developed internal tools to check out the trust of 301s - that's why the effects can be delayed over even a long time, and in some cases, the link juice will never show up. But it is also common for one business to legitimately acquire another and visitors looking for the old business website need some TLC.

And that's why I suggest welcoming the previous business's customers on a dedicated 301 landing page, rather than just using a 301 to the home page. The dedicated landing page will have navigation into the regular site and home page - the link juice should flow.

[edited by: tedster at 9:59 pm (utc) on Oct. 13, 2009]

Yeah I was not taking a shot at anyone, just had a mental image of a whole lot of webmasters racing off on a domain buying frenzy.