I can't really speak knowledgeably about your attempts, because I don't have enough background. There are lots of reasons why someone may not respond:
1. They're not on twitter when you send the reply, which may mean that by the time they come back, the data is "old"
2. Some people don't know that it's okay to respond to "old" tweets
3. They might not like the advice you've given them
4. They didn't really ask a question
5. They don't know how to respond
6. They are inconsiderate jerks

I don't care what the reason is. I follow people I find interesting. If they don't follow me, that's okay. However, if we're following each other, and they don't respond when I talk to them, I unfollow, because they're not really trying to be social, and then fit in your category of "asking to appear to be sharing." In the short attention span theater of twitter, I don't have time for people like that.
My recent post Falling on Deaf Ears

If you want to measure the value of twitter, you need a much larger sample than one day. You need to look at trends over time. Also, were the helpful comments sent to people who are following you, or strangers? I send helpful hints to strangers often - some people don't respond. No big deal, because the interaction with people who follow, or will continue to follow, is most important, because that's what builds relationships.
My recent post 10 Twitterisms We Wish Everyone Would Stop Using