Of course the Linear system offers Blogs, but did you know you can provide discrete blogs to your clients? Sure enough. These blogs are tied to their client information so that whenever you see data for a client (i.e. directory listing, calendar event, etc) there will be a link to their blog.
Your site would have a page which listed all non-Site blogs. And, if a client's blog ever became popular, you can easily designate it to appear with your Site blogs.
These discrete client blogs have all the power of your Site blogs including visual uploading, searching, password protection and multiple author permissions.