A thematic bundle seems necessary because people buy apps based on use case as tools. The consumer is exceedingly unlikely to have heard of randomly selected application_foo unless it has already been marketed successfully. Which defeats the benefits for app-makers of getting in on a promotional bundle.
Groupon can get away with decreased items per bundle (1) at a higher frequency (daily) because: A) they have a ton of repeat viewers, B) each individual product use-case (ex. restaurant) is usually extremely obvious and non-specialized in appeal
Groupon can get away with decreased items per bundle (1) at a higher frequency (daily) because: A) they have a ton of repeat viewers, B) each individual product use-case (ex. restaurant) is usually extremely obvious and non-specialized in appeal