Is the series more like a linear one that every episode counts as a part of a story or that it has filler episodes where just random stuff happens and the events are not spoken of anywhere in the future?
the latter. the filler episodes (known as "slice-of-life" episodes) are the majority of the series' makeup in episodes. there is little-to-no connection in terms of a plot/storyline, however a couple episodes will feature continuity but generally not something worth jumping fences over. the various single episodes give bits and pieces of information related to their world that fans have taken to recreate the very vague history.
the two-part episodes are where the real big storylines are found. the first two for example are obviously connected, and the second connects a few things related to the entire first season near the end. still, these stories are confined to their own episodes.
in the end, the series isn't connected in a deep way. some things are spoken of and mentioned in the future about past events, but it isn't often. the reason behind this is likely because it's a
little kid's show. little kids don't really have the attention-span (or interest probably) to keep up with a 26 (or longer) episode story. that's something for the more older kids.
(do note that not every adult cartoon has a story either, Futurama, for example, is a personal favorite and there are very few episodes that actually link up. there are a couple details that last, such as Fry's love for Leela, but simple details like this also exist throughout Friendship is Magic too)
