Shared SSL means you use your Hosting Provider's SSL Certificate. This will usually result in something like https://yourname.example.com. The benefits are that they are generally free or inexpensive to use and require no maintenance on your part. The downside is that a visitor attempting to purchase a good or service from you may be turned off by the fact that they were referred to "an outside domain" to finish their transaction. Most of the time people do not mind (or notice).

A regular SSL Certificate means you purchased your own certificate for use with your own domain, for example https://secure.example.com. This benefit to this is that it looks more professional to your customers. The downside is annual costs and maintenance.

ProExe do not recommend shared SSL.