People use the thumbs in different ways.
Some people use them as a type of commentary on the thread, others use them to keep their personal viewing pages clean. They thumb things down that they're not interested in - not that they necessarily dislike the topic, they just aren't interested. For example, there is a smallish group of people here who like word games (I'm one of them
). A lot of people aren't interested in word games so thumb all of them down so they don't need to see them in their feeds.
The only people who won't see your thread are the people who have thumbed it down (at least that's my understanding of it). Other people will still see it.
Interesting as well as good thread titles can be helpful in getting people to look at your threads. In the same way, precise tagging can sometimes help.