A complex site calls for a more comprehensive package that provides database support and application development platforms (e.g. ASP.NET, ColdFusion, Java EE, Perl/Plack, PHP or Ruby on Rails). These facilities allow customers to write or install scripts for applications like forums and content management. Also, Secure Sockets Layer (SSL) is typically used for websites that wish to keep the data transmitted more secure.
Shared hosting is like an apartment building where the building or server has many tenants or hosting accounts sharing the space and the utilities. This works just fine if you have a small family but if everyone in the building has ten roommates move in who are constantly running the water and using the wifi then the water pressure and wifi speed start to suffer. The key to shared hosting is that it is meant for small business websites, sure you can pack the roommates or files in like sardines but it will really be uncomfortable.
Because web hosting services host websites belonging to their customers, online security is an important concern. When a customer agrees to use a web hosting service, they are relinquishing control of the security of their site to the company that is hosting the site. The level of security that a web hosting service offers is extremely important to a prospective customer and can be a major consideration when considering which provider a customer may choose.
Many services offer so-called unlimited or unmetered service for whatever amount of bandwidth, disk storage and sites you use. It's important to understand that most terms of service actually do limit the definition of "unlimited" to what's considered reasonable use. The bottom line is simple: if you're building a pretty basic website, unlimited means you don't need to worry. But if you're trying to do something excessive (or illegal, immoral or fattening), the fine print in the terms of service will trigger, and you'll either be asked to spend more or go elsewhere.