You could think of the sites that share your server as your roommates; there's really not that much separating you from them. Sure, you can close the bedroom door, but they can still cause nightmares for you in the kitchen and the bathroom. In web hosting terms, all the sites share a single server's resources, so huge traffic spike on Site A may impact the neighboring sites' performances. It's even possible that another site could take down the shared server altogether, if it crashed hard enough.
People often think that a web host is the main cause of a slow website but, this is often not the case. When picking a provider, it's important for find a hosting provider that is close to your users and has a good amount of RAM and fast CPU power. Beyond that, it's often the way the website is set up that slows it down for users. To ensure that your website speed is optimal for users you need to make sure you pay attention to the following:
If you've ever been worried about the tremendous amount of power large data centers consume, you might want to sign up with Green Geeks. The "green" in the company's name reflects the Green Geeks' commitment to the environment. It purchases three times the energy it actually uses in wind energy credits, essentially putting energy back into the economy. The company does this through a form of renewable energy certificates, which, while a bit complicated, means that it's not just energy neutral, i's actually helping fuel the green energy economy.
Similar to the dedicated web hosting service, but the user owns the colo server; the hosting company provides physical space that the server takes up and takes care of the server. This is the most powerful and expensive type of web hosting service. In most cases, the colocation provider may provide little to no support directly for their client's machine, providing only the electrical, Internet access, and storage facilities for the server. In most cases for colo, the client would have his own administrator visit the data center on site to do any hardware upgrades or changes. Formerly, many colocation providers would accept any system configuration for hosting, even ones housed in desktop-style minitower cases, but most hosts now require rack mount enclosures and standard system configurations.
^ March 16, 1992 memo from Mariam Leder, NSF Assistant General Counsel to Steven Wolff, Division Director, NSF DNCRI (included at page 128 of Management of NSFNET, a transcript of the March 12, 1992 hearing before the Subcommittee on Science of the Committee on Science, Space, and Technology, U.S. House of Representatives, One Hundred Second Congress, Second Session, Hon. Rick Boucher, subcommittee chairman, presiding)