The soured relationship between the Interactive Advertising Bureau (IAB) and Mediapost - the two groups that last year produced the Internet Advertising World event together - worsened last week when the IAB said it is suing to prevent Mediapost from using the title of an online awards program used in last year's conference as the core brand name behind its own competing conference. The IAB has been very aggressive in trying to box out Mediapost, deciding to schedule its event - now run with AdWeek - to run during the same week as Mediapost's OMMA event. It is claiming co-ownership of the OMMA brand name, while Mediapost's chief said in a release that OMMA was a Mediapost-invented property that had been only on loan to the IAB affair.