Internet faxing services can be divided into three groups, each of which has a different usage pattern and volume requirement. The three groups are:
Home User or SOHO* User - These are typically low volume users. They need to send or receive faxes only occasionally, and might prefer not to pay a monthly subscription to get service. If you're in this group, you may want to look at providers like eFax and Callwave.
Office/Network - These are typically a medium volume users. They have everyday faxing requirements for faxing from several locations within the office and even from geographically-dispersed office locations. If you're in this group, you may want to look at providers like Protus and Maxemail.
Enterprise/Production - These are typically high volume users. They need specialized, customized, high-volume fax solutions from enterprise applications. If you're in this group, you may want to look at providers like InterFAX and Venali.
Different providers may cater to different types of users, and it's important that you select the right type of provider, so that you receive the proper level of attention you need. A provider who is set up to offer customization to enterprises who need production faxing may not be able to provide the hand-holding that a home user may require, while providers to home users may not have the proficiency required to suggest production faxing solutions.
Be sure when shopping around to verify that your provider can provide the level of assistance that you require.
* SOHO = Small Office/Home Office