Age of site factor

How does Google perceive web sites in regards to "age of site." For instance, the Google SEO reference site at seomoz
mentions that Age of Site is very important and is based on:

"Not the date of original registration of the domain, but rather the launch of indexable content seen by the search engines (note that this can change if a domain switches ownership)."

Question: Recently, our company migrated and redesigned an acquired web site to our servers and under our own management. The domain name stayed the same. After the migration, we updated existing content and added more articles (i.e, added more content). Since we changed ownership, does that mean that Google views the acquired site as a brand new site?

TIA

Did the overall theme of the website change?

Hi Alloemseo,
No. The overall theme of the website did not change.

We've done similar things with our comapny in that we bought a website, completely redesigned the layout and added content to it (with more than one domain actually). It didn't seem that G saw it as a brand new domain, in fact many of the new pages ranked immediately for thier keywords. The one domain was registered in 1996 and we redesigned it in 2006. It is still doing very well today. So if you're careful you can keep all the power of a domain even after it has changed ownership.

Thanks again! I think we redesigned and restructured URLs too soon after the migration.

Supposedly it does matter but like everything else I think it's pretty tough to verify. I believe in theory older sites will rank better than newer sites all other things equal. Whether that's true or not?