They certainly do. I've found that feature to be pretty buggy, personally. Command + tilde is faster than clicking a drop down and waiting for the switch.
When I was using it, not all of their services were supported, and to get into the right account I'd frequently have to log out (which logged me out of every account).
Another fun one was clicking on Google Docs links. It rarely was using the right account and allowed me to go forward. Usually got the "Please request access to this document" message.
You're talking about Google's multi-login, which allows you to log into Google with multiple accounts. This thread, however, is about Chrome's profiles, which lets you open multiple browser windows each with a different profile (i.e. cookies, Google account, extensions, etc.).
>You can actually sign in to multiple google accounts and switch between them (at least for email / docs - not analytics / other services). I can't remember exactly how to do it, I think you need to enable multiple sign in on the account first.