You can join a second and subsequent projects as follows: Run the BOINC client, and select the Attach to Project command. Enter the project's URL and your email address and password. You don't have to use the same email address, but if you do so the accounts will be 'coupled' in terms of preferences and statistics.
Each BOINC project has its own copy of your general preferences. When you edit your general preferences on a particular project, initially it changes only that one account. However, BOINC will eventually
Be careful about editing general preferences at different projects. If you change your general preferences at project A, then edit them at project B before the first changes have propagated there, the second changes will overwrite the first. To avoid this, pick a 'home project' and do all your edits there.
Each host attached to a project has its own record in the database of that project; this record includes the location (home/work/school) of the host. BOINC doesn't try to make these agree - it's possible that a given host has location 'work' on project A, and location 'school' on project B. When the BOINC Manager starts up, it shows you that locations of the host on all the projects to which it's attached.
A host's location on a given project determines which project preferences are used: i.e., if a host has location 'home' an project A, and you've defined separate project preferences for 'home', it will use those preferences.
The choice of general preferences (if you've defined separate preferences) is determined by the host's location on the project from which the general preferences were propagated, i.e. from the project where you last edited them. So if you edit your general preferences on project A, a host's location on project A is 'work', and you've defined separate general preferences for 'work', the host will use those. "; page_tail(); ?>