What is semi-dedicated?
Semi dedicated means that you will share a whole server with just a few other people, this means that you get a huge amount of storage space, a huge amount of bandwidth and a huge amount of ram, and you are not sharing rescources with with a huge numbers of other people, leading to better response times etc

Its like having your own server without the higher running costs

You also get your own dedicated IP address that is only linked to your account, so you can have a private SSL certificate, Direct IP address to your domain which helps when you need to access ftp or website and are having domain problems.

Who's it for?
The plan is for people and businesses that are serious about their website, having a semi dedicated plan means that your website is not slowed down when a huge number of people are on your website, if you are expecting a high amount of traffic and want your customers to have a good experience on your site then this is the plan for you

So what are the Benefits?
A lot cheaper than purchasing a server just for yourself
You only share server rescources with a small number of other people
Dedicated IP address