You can create as many sites as you want in a multisite network. In each site, you
can add as many users as you need.
Sometimes, the same person needs to work on more than one site. For example,
one person might need to contribute to different blogs maintained by different
people. Or an administrator who manages one site in a network might also want to
contribute to another.
To understand how to deal with this, you need to realize that a multisite network
maintains a master list of all the users who belong to any site in the network. Each of
those people has subscriber privileges on every site. (As you learned on page 370,
subscribers are the lowest class of WordPress user—they can’t do anything more
than read posts and write comments.)
In addition, you can give people special privileges for specific sites. For example,
you might make someone an administrator on one blog and an author on another.
In this case, there’s still just one record for that user, but now it’s registered with
two different sets of capabilities on two different sites.
NOTE Happily, WordPress makes people log in only once. When visitors move from one site to another in
the same network, WordPress remembers who they are and determines what privileges they should have on
If you choose Users→Add New on the network administration dashboard, you can
add people to the master list (Figure 11-28, top). But WordPress won’t give new users
any special privileges for any site.
Life is different for ordinary site administrators. Consider what happens if an administrator
named Suzy logs into her dashboard. When she chooses Users→Add New, she’s
not given the option to create an account for someone else. Instead, she can invite
an existing user to take on a more powerful role on her site.
One potential problem with the user registration system is that it can create a lot of
extra work. For example, if a site administrator needs to add someone new, he needs
to ask you, the network administrator, to create the account first. To circumvent this
restriction, go to Settings→Network Settings, choose “Allow site administrators to
add new users to their site,” and then click Save Changes. Now site administrators
can add new people to the master list.
Another problem occurs if one person contributes to several sites. In that case,
someone needs to visit each dashboard and invite the user separately to each site.
If you’re not the sort of person who likes to spend all weekend tweaking WordPress
settings, you may want to enlist the help of a plug-in like Multisite User Management
(http://tinyurl.com/multisite-um). It lets you set a default role for each site in a multisite
network. Then, when you create a new user, she’s automatically registered on
each site with the default role you chose.