You could try using some sort of rss aggregator, like "page modified" that scans normal html/php pages and looks for specific items, as per your set up and have it watch your "posts" page, not sure if that will work.  Or, along the same lines, use a simple scraper or automation software to check the same.  But, I would ask the admins here first, before running any kind of behind the scenes software that causes extra traffic for the site.  Just you is one thing, but if it catches on, then there are hundreds of people using it to watch their posts and such and that could almost double the traffic in some cases.  If  it is one or two threads that have your interest in watching, either add them to your watch list, or put that thread in your bookmark toolbar and use that as a starting page for coming to the forum everyday.