Go ahead and report any topic you consider as low quality and that breaks the rule, there will be no negative action for you, and action will definitely be taken against the thread or reply if the moderator considers your report to be good/correct. You do not have to be reluctant to report bad posts, just make sure you are doing it accurately, the forum actually appreciates such effort and contribution, that is why there have been numerous discussions on awarding users with reporters badge for their efforts to rid the forum of bad posts. There is as yet no official reporters badge on the forum, though we may get one soon, but there is somewhat of an unofficial Bitcointalk reporters badge.  Here is also another thread that shows the forum appreciates users making good reports on low quality posts, so if you start now, you can definitely do as good in the long run