CEDAR KNOLLS, N.J. – Need more reason to make sure your electronic communications to your members needs to be justifiable, welcome and distinguishable? Consider this: Spam now constitutes 50% of all e-mail, according to a new report from analyst firm Probe Group. And up to 80% of the e-mail sent to large Internet service providers like America Online and MSN is unsolicited commercial e-mail. "E-mail has generally been considered one of the most useful and utilized features offered by the Internet. However, spam threatens the usefulness of e-mail as a communications medium," says the firm's research director, Alan Mosher. There are tangible and intangible costs: Besides angering consumers, Mosher suggests that spam has forced ISPs to add e-mail servers and storage capacity to handle the increase in traffic volume. "And it also has forced ISPs to implement additional tools that give subscribers greater control over what messages reach e-mail in-boxes. ISPs have also had to add third-party services to intercept the bulk of spam before it reaches subscriber in-boxes," he says. Those filters, also put in play by individual consumers, are something else credit unions have to contend with, to make sure that their e-mails get to their intended recipients without being blocked.