I guess it depends on how you define "reasonably" private.<p>E-mail is a little different than something like Facebook, initially, because Facebook persistently displays your data whereas email is a one-time thing; you list the people you want to see the email, send it, they receive it, and it's offline in the meantime, it's not a shared asset. So, in that way, it's not subject to the same kind of possible privacy alterations that a social network where your data is always displayed and available is.<p>That said, e-mail is rather insecure. While it might take more effort than sending a friend request, intercepting an email is still pretty easy, and people at Google can access your data. While it's not likely that there are Google employees going through random email boxes for fun, the contents and metadata of your emails can be disclosed through subpoena, security breaches, or other means.<p>So, while there is some privacy in a normal Gmail account, say, enough to keep a casual home or business user satisfied, that privacy is still highly dependent on competence and goodwill at Google.<p>The bottom line is that if you have something that really needs to be kept private, you need to at least encrypt your data with something like PGP. Your data is not private at Google and it is certainly not private on Facebook or Myspace, whose business depends on increasing pageviews and time spent on site at minimal cost (i.e., making extant content available to more people).