(Neil Roiter, Senior Technology Editor, TechTarget) It's tough to keep pace with the explosive growth of spam if you build an in-house email security solution. Commercial software and appliances are more efficient and have the features to make life easier for IT and end users, but even so, managing email security is just one more chore for companies with limited staff and tight budgets.

Small wonder Software-as-a-Service (SaaS) is increasingly popular among midmarket companies, and it's very likely a good choice for your organization.

The biggest consideration driving this trend is overtaxed staff. Even small companies have to deal with spam volumes that have grown far past the point where some basic filtering rules are sufficient. In-house antispam, using open source software such as SpamAssassin probably is no longer robust enough. What was initially a good, inexpensive solution put together and maintained by your technical hotshots, grows increasingly burdensome because either your hotshot is gone, or you're spending too much time keeping it up to date.

Cooling and high availability factors to consider
High availability is another consideration. Email appliances are very reliable and unlikely to go down, but it's a consideration. If you can't afford an outage, you'll need to run a second appliance in parallel in case one goes down. That's not a very attractive option for small organizations because of the extra cost and maintenance. On the plus side, vendors typically offer deep discounts for backup appliances.

On the other hand, SaaS vendors are well established with strong, redundant infrastructures, and SLAs that guarantee availability.

Weighing appliances versus services
If you go the SaaS route, you're treating email security as an expense rather than a capital expenditure. If that's your preference, one of the prime advantages is that you pay as you go for the number of users. So, if your company has laid off employees in this tough economy, you can ratchet down and increase your costs as your employee count goes up. That may be more attractive to management than additional capital investment.