While using this practice it is important to realize that your shared hosting shares a common IP address block as well. This means that the search engines to not lend as much credibility to your backlinks because it’s obvious that the referring link is coming from the same hosting account.

If this is your practice, it is important to use dedicated IP’s for each hosting account; preferably from different webhosts or a webhost that assigns different Class C IP Addresses. Personally I recommend using a host like IX Webhosting, that offers up to o8 dedicated, class C hosting accounts for nearly the same price as Hostmonster, Hostgator or Lunar Pages (for Windows Hosting).