Right now you are reading WordPress right? It is also one of the site hosting platform. But it is not having the document management feature. It is having blogging and collaboration.
My insight in future about SharePoint is the one of the popular site hosting tool like WordPress these days. Almost every body having blog and few are having social community accounts. But in future every business will be maintained under SharePoint portal only.
Now a days few companies are using SharePoint and few are still sharing their documents using LAN and internet. Its fine but there are lots drawbacks. To avoid all those SharePoint is introduced by Microsoft. Every business will have SharePoint portal to share their insights and content.
For more information what is SharePoint? Please visit the below page once.
Here, you can find the steps to download the SharePoint software too and you can created online as well.