Jonathan Zdziarski, the developer of the DSPAM open-source Bayesian spam blocker, believes IT departments of most small- to medium-sized businesses are afraid to try free programs or meet resistance from higher-level company executives.
"Most mid-sized companies just pull an appliance off the shelf," he said, noting there are "a million anti-spam companies out there with boxes loaded with a hodgepodge" of solutions. "Thats one of the reasons these businesses, if you ask them, are convinced spam filtering is ineffective … A lot of these companies are running technology thats five to seven years old."
Some popular, commercially-distributed solutions say they employ Bayesian filters. When used alone, as in DSPAM and other similar program, these filters use statistical analysis to yield incredibly accurate spam control.