Why are subjects locked?

[RGF]

I have seen a few discussions locked - okay the discussion of the type of camera of the President could be politic and hence leading to flaming so I can understand that one, but others seem harmless enough.

Just wondering about this - don't want to run foul of the rules but would like to understand what is not appreciated/ appropriate.

thanks

[neuroanatomist]

I infer several reasons.  Overly contentious to no point, descent into a flame war, old threads resurrected to no apparent purpose have all been reasons I've seen threads locked.  I believe an OP can also lock their own thread (or maybe just delete it, not sure...).

[RGF]

I infer several reasons.  Overly contentious to no point, descent into a flame war, old threads resurrected to no apparent purpose have all been reasons I've seen threads locked.  I believe an OP can also lock their own thread (or maybe just delete it, not sure...).

I would hope (which means nothing since I do not have a vote here) if a thread was locked because it was redundant with an old topic, that the admin / moderate would point to key discussions on the topic. 

[Mt Spokane Photography]

I infer several reasons.  Overly contentious to no point, descent into a flame war, old threads resurrected to no apparent purpose have all been reasons I've seen threads locked.  I believe an OP can also lock their own thread (or maybe just delete it, not sure...).

I would hope (which means nothing since I do not have a vote here) if a thread was locked because it was redundant with an old topic, that the admin / moderate would point to key discussions on the topic.

I do not think that threads get locked for being redundant to old topics.  Sometimes several members post the same topic at about the same time, they are merged, not locked.
 
 
I saw one yesterday where a person asked for help last June 2012, and suddenly someone started posting telling him how to fix his problem.  It was probably locked because further comment did not make sense.
 
There are also those with dozens of flaming posts that need to be stopped, and locking the topic is sometimes the best solution.