If you don't have a manual action but have some kind of algorithmic penalty, do you guys think that this is likely to be on-site content?
in my case the algorithmic penalty was pretty clearly attributable to a mass 301 redirection to homepage, where i didn't see the consequences.
as said, the penalty duration is determined by a) severeness and b) recurrence of the violation. mass 301 redirection is quite a heavy violation in google's eyes. so when the trigger is pulled after detection (in my experience 2 weeks or so) you get degraded for example for two months. if it's not the first violation of the same kind, you get punished for a longer period, for example four months.
google seems to record your violation stats - the gap between two violations of the same kind probably doesn't play a role. due to the exact timing of the penalty duration, there also seems to be no escape to shorten the time frame and get back your former rankings earlier. so if you accidentally screw things up, you have to wait the complete time frame even if you correct your faults immediately after you have noticed (which is harsh imo).
there are very likely other violations that trigger an algorithmic penalty for an exact period. maybe duplicate content, cloaking, hidden text, keyword stuffing..
would have liked to read more about this stuff here in this forum. especially the penalty durations for different violations are of interest. i mean, the procedure is relatively straightforward and obvious and i can't imagine that i'm the only one who has experienced this.
[edited by: moTi at 2:49 pm (utc) on Mar 27, 2014]