Compiled ByDeborah Austin In the B2B e-world, profitability may follow longevity. Of B2B firms online for three or more years, 46% are profitable today -- compared with only 32% of B2B firms overall -- shows a new study by ActivMedia Research. But in contrast to the business-to-consumer (B2C) sector, most B2B firms don't expect their online business to ever exceed offline, shows the study, "Online Success Strategies in B2B Markets." Only 18% of all B2B businesses sell directly at their Web sites, the study found. But overall, 43% have seen a business downturn since the Internet's advent. So, ActivMedia predicts, many more will start selling online in the next two years as a matter of survival. Peterborough, N.H.-based ActivMedia Research conducts custom and syndicated research on Internet commerce.