There's an increasing raft of content aggregation (or 'channel making') tools becoming available. This is a smart approach to the market - they take little development effort and are essentially parasitical - taking their content from existing and popular UGC sites. World TV is the latest such tool, with Mogulus also recently coming out of beta. Meanwhile, streaming network giant Akamai is also offering channel building functionality through its recently launched Media Framework.
The reason this is a smart place to be is that everyone else does the work whilst it is very easy to insert and control the advertising between the clips in the channel playlists. It also plays into the whole social networking boom by enabling internet users to add their own channels to their pages on Facebook and other similar services.
The major downside is that Flash provides poor support for advertising (although being widely used for producing ads on websites), but I'm sure that there are many, many people working on this issue in the hope of world video domination.