shortbutsweet saidHave you ever poured your heart into a post, spent a great deal of time writing a thoughtful reply, or given exceptionally valuable advice to an OP who never responds and doesn't participate in his own thread? How does that make you feel?
Without full context I might feel annoyed or ignored. That said, it's important to recognize that just because someone doesn't respond to you it doesn't mean that they haven't read or haven't considered what you've written. It also doesn't mean that they won't read it or won't consider it, because it's possible they haven't. Forum posts (and text messages, another area where a variation of your question comes up) are asynchronous forms of communication, meaning that communication is intermittent and not dependent on an instant answer. Meanwhile, talking over the phone or having an in person conversation are examples of synchronous forms of conversation, where some form of response is necessary to continue communication.
Somewhere out there someone reads what you write. In my short time here I can't begin to tell you the number of times I've received private messages about a post I've made, sometimes from an OP. Sometimes it's because they don't want to get involved in the thread and just want to read responses, or because they have something personal to share that they'd rather keep between us. People then who have only read one of those posts and see little to no response to it within the thread would be mistaken to think that there was no response.
There's always more context and more going on than what you can see at surface level.