In a social networking site, an automatic party invitation mechanism is being developed to invite all fans of k movie genres to a special private screening of a new indie film at a nearby theater that...

In a social networking site, an automatic party invitation mechanism is being developed to invite all fans of k movie genres to a special private screening of a new indie film at a nearby theater that spans across these genres (i.e., the movie is an ActionAdventure/Comedy/Drama, and users can be defined to like one or more of these genres). The developers are tasked with identifying a clustering algorithm suited to ensure the maximum number of people with these common interests, but they also need to be able to re-use these clusters for future projects (i.e., a Drama/Romance film). Name at least three considerations they should make for the algorithm to use.