I have always worked along the lines of most people here and the article. A Senior Developer is one that has amassed not only solid development experience across multiple projects but also has a solid knowledge of your product code base. Someone that can just get stuff done and leads by example. Applies best practices and is pragmatic and always add's value to the code base.

I agree that titles are handed out too easily however, developers are partly to blame here. I have held numerous titles over my career but they are meaningless. Experience is built over years for learning and applying your trade and for those that want to continue doing that where do they go after "senior"? If developer's were not so desperate for the title then this discussion and the questions being raised would be moot and we'd all be back coding.