@Zaktor There is some influence. Two things that come to mind:
default post length limit (500 characters)
how the server renders “Page” ActivityPub objects (e.g. Lemmy posts)
For example, many comments made in this thread could not be made from a Mastodon server. All Lemmy posts show as just a title and link with a blank body. These application behaviours have a direct influence on what types of conversations take place by people from Mastodon servers.