Disclaimer: I was
about to reply here but it was getting lenghy so I thought I'm better off posting it as a full idea.
I note that you cannot tell from the topic list if a topic has been resolved on not. You have to open it and check if any posts have been marked as "solving the question".
I think the least that should happen is to somehow mark topics on the the replies/followers counter as resolved/implemented/answered. Perhaps a different icon depending on if the company claims that it's solved or if the user says it's solved.
If a topic has both user and company agreeing that it's solved, then a [solved] text could be prepended to the title and people will be able to filter out topics marked as such. This would then be used by people to see how many topics are still open, which should provide an incentive for the company to mark them as solved if they indeed are.
An alternate format could be where a topic could be marked as [solved] by the company, but the user has an option to dispute this. This would again be visible in the list with some kind of special (alarm) icon. This should hopefully trigger the company to provide a working solution in order to avoid having too many of these nasty ones.
Indeed, now that I think about it, an option to do the above and then giving users the option to see all disputed topics, might be a nice incentive for companies to focus more on solving issues and possibly boast about the low number of disputed ones ;)