Most people that own a website have heard about Title tags either from their web developer, or perhaps in an article that they have read. Net101 created a video series a while back that deals with many basic web concepts including Title tags.
If you would like to learn more about these tags, please take a moment to watch this 1:25 minute video, I think you will find it will answer many of your questions, and perhaps provide you with a bit of knowledge for the next time you speak with your developer.