Posting in the Java forum of the community I have seen one thing happen more often than not. I have seen posters post onto a thread that has been solved years ago, but just weren't marked as solved by the OP. Take for example this recent thread in the forum. This thread was started on 20th April 2004, to which the first reply itself was 15 days later. On that day itself, the OP thanked the replier and never posted again on the thread which makes me believe that his query might have been solved. But he didn't mark it so. Then more than an year later somebody posted onto the thread again asking for the docs for the s/w, to which the first reply was four months later. Today after lying there for more than 3 years the same thread was revived by a poster asking for help using the s/w. To which I have posted my reply suggesting the poster to start the new thread siting that this one's more than 4 years old.
The point I want to make over here is, can't we have some auto-marking mechanism for threads which identifies the time the last post was made onto a thread and if this is more than some pre-specified value mark the thread as "solved". One thing that could be done before doing so is to check that the last post isn't by the OP, which would mean that somebody has "offered" something to him but he hasn't returned to it.
Yes it is perfectly possible that the OP's query might not have been solved, but his non-return could be safely taken as a green signal to close the "issue". Because it means one of the two things, either the query is solved and the OP has just forgotten to (or not taken care to) mark the thread as "solved", or he doesn't want to get it solved anymore. There can be a broad category of causes for non-return that might fall into this category but what it more or less means is that, he isn't interested in the solution (atleast from here) anymore, and that should suffice us to proceed towards marking the thread solved. I am sure that this decision of auto-marking would be correct on the community/forum's part but for a rare number of cases in which the OP always has the option of marking the thread unsolved again and opening a request for help on the topic again. Also he could check the reply offered to him earlier and then decide whether or not to open the thread again.