Web mail is often free, or offered at low-costs with features tailored to small businesses. But e-mail may be too important to entrust to a free or cheap Web-bases system, warns Roger Matus, CEO of e-mail archiving firm Inboxer.

Potential pitfalls include the risk of downtime. For example, Google’s Gmail made headlines after a few recent outages lasted several hours.

Also, most of these services give users little recourse if messages are lost — which can hurt the bottom line if, for example, messages to and from potential customers or clients don’t get through. Gmail’s service agreement says Google is not responsible for “any damages or loss of profit or harm to business reputation that results from use of the service.”

Our conclusion: Gmail (and others like it) are fine for home use, but if e-mail is critical to your business, you may want to spend the money for a more strictly managed system.