Are questions related to sniffing traffic (tcpdump) or debugging command-line tools are on-topic?
For example tracing php, memcached processes using dtrace or strace?
I'd say yes if they're applied for reverse engineering. If it's for development/debugging, StackOverflow might be a better choice. Check also previous discussion
It depends on who you happen to encounter to be honest. I would say Yes, but some people are so pedantic that almost nothing seems on-topic. I mean, what kind of community do we have when a person has to ask if their question is on-topic before asking it?