Google Groups tend to not trim the quoted text which makes following a thread a major nuisance.

That doesn't sound like a googlegroups problem as much as a rookie
poster problem... I use googlegroups but I also manually trim my
posts. Like Ramy, I too access it from different computers all over so
it makes for a really convenient universal interface and the spam is
easy enough to ignore thus far. With googlegoups though, I have to
switch the main page to display 'Topic List' and NOT leave it on
'Topic Summary' which it defaults to or else it's basically unusable.

-Paul