[mothered]

what grave digging is not allowed? give me one example. So I know if I can post it or not.

It's difficult to be precise.

A simple example, Is If a thread Is 2 years old and the OP hasn't been active for that duration. The link contributed In the thread  Is also dead. If a member posted something like "Thanks for the share",  apart from an LQ reply, that's considered grave digging.

I see also what if the tutorial or tool link is not active anymore and the thread is like 2 years old right. Would he be better to reply and report the posting?

That would depend on the activity of the OP.

There's no purpose In replying, If the OP also hasn't been active for that duration. There's no harm In leaving the thread open- members are known to return after many years of Inactivity.