Roll scumming is practice to roll multiple characters in order to get certain bonus (Steel man challenge is considerably faster and easier if you start with Scroll of danger for example), which might include better stats, special birth messages, extra random talent or specific starting items..
Prior to Steam release rolling characters for starsigns was used quite often (or game RNG seed was modified by starsign selectors). Adom server has inbuilt character roller (not updated for the latest versions) which allows for roll scumming at extreme levels.