A two-sided network typically has two distinct user groups. Members of at least one group exhibit a preference regarding the number of users in the other group; these are called cross-side network effects. Each group's members may also have preferences regarding the number of users in their own group; these are called same-side network effects. Cross-side network effects are usually positive, but can be negative (as with consumer reactions to advertising). Same-side network effects may be either positive (e.g., the benefit from swapping video games with more peers) or negative (e.g., the desire to exclude direct rivals from an online business-to-business marketplace).