I’m just here to tell you that this is a very US centric view. I’m not from the US and, outside of random internet posts, there are no records of any of my political associations, past or present, and I’ve voted in all local and national elections for >20 years. Seeing as extremist forces are unfortunately currently gaining power over here, I REALLY wouldn’t want any type of public record even hinting at who exactly I’ve been voting for.
Feeds are aggregators that show you posts that fulfill certain criteria, such as mentioning keywords (which can include but is not limited to hashtags). They’re a lot more versatile than just hashtags. I can’t tell you why they chose the # symbol to represent feeds ┐( ∵ )┌
On your profile you have a following count, that’s where you’ll find a list of people you follow.