We have a dozen or so sites, as well as the occasional subdomains so:
example.com example.co.uk us.example.com etc
We have been using separate GA codes for each site. This works fine, but it means that adding a new site means getting a new code and we can't tell overall stats (e.g. how many people have visited all sites etc). If we went the one code route and set up separate profiles for each domain/subdomain:
1) Should we use _setDomainName("none") or _setDomainName("www.example.com") and _setDomainName("www.example.co.uk") etc
2) Will each domain profile treat the other domains as separate (e.g. will we tell on example.co.uk how many people visited from example.com and completed goals etc)
3) Are there any disadvantages to this method.
This post from the Google Analytics blog details how to set up a GA account for each site, and an overall 'rollup' account which sits on top - this will let you give separate GA admin control for each site, where you can dig deep into each site's account, and show cross-site referrals, and the rollup will give overall numbers (but I don't think it's going to report on unique visitors across the collection of sites).
http://analytics.blogspot.com/2009/09/advanced-structure-your-account-with.html
来源：https://stackoverflow.com/questions/2008572/multi-domain-setup-on-google-analytics