Well, they just
call it "endless scrolling", technically, you should reach the first post sometime... ;)
As far as I know, there's not a really handy solution to this. However, following the "filter by date"-option as explained in FAQ soup
here, try this:
Add
?date=YYYY-MM-DD to the URL to show posts on and
before that date.
Put in the first of the month where you think you joined Soup.
Go back or forward by a month at a time. Forward if it says "This user hasn't posted anything yet.", back if you see lots of posts.
Then you'll get the "You've reached the end" message if you've got endless scrolling activated in your soup. Or, if it's deactivated, you'll get the "newer [posts]" button at the end with no "more [posts]". I think it's easier if you deactivate endless scrolling for this.
Worked for me. =)
(Also, I've tried filtering by date
and content type to see if you could just ignore imported feeds, but that one doesn't work. =/ )