Although many internet users now delete spam before opening it, these unwanted eMail messages still steal bandwidth when passing through school or district servers. MicroWorld Technologies Inc. claims its X-Spam software is more effective at catching spam compared with other anti-spam solutions, including free and paid programs. X-Spam, the company says, is highly intelligent software that uses an advanced heuristic filter engine combined with two proprietary features–Regular Expressions and Meta Tests–that refine spam identification to an art. Regular Expressions are rule sets to identify spam, and each one has a score associated with it. When eMail messages are tested for spam, each time they test positive for a rule, this score is added to the total. Only when the total reaches a certain threshold value is the mail identified as spam. Meta Tests allow users run further-refined tests to identify spam. The tests allow users to combine multiple expressions with qualifiers like and, or, = , >,<, and so on. With these tests, X-Spam blocks the unwanted mail before it enters the mail server. A one-year subscription to X-Spam ranges from $2.27 per user for 2,500 users to $7.20 per user for 10 users. Multi-year pricing also is available.