In terms of news algo:
I'm not an expert but it's been around for a while. Because most of the Reuters and Bloomberg news txts have a simple txt template for news, I tried developing a system out of it. Obviously, the market reacts to a similar news differently. The impact of the news differs based on the underlying market condition and it became a big task at hand to figure it out.
I'm not an expert in liguistics or computer science (and smart) so I didn't get into the rocket science stuff but I did find a few edges while researching and brainstorming to make the news system work. My conclusion became that the newsfeed itself was a form of a trigger with edge, and the significance lies with the setup part. So I took the news trigger out and put in another trigger that worked better.
Though, it was interesting how a series of news affects the market gradually. Also, as a hypothesis, how it correlates with changing market condition. From my research, solely, the sematics of the news itself don't matter so much, it's more about quantifying(maybe symoblize is a better word) the news and deriving a "bias" from the series.
Again, I'm not an expert or academic. Hopefully, someone else can shed some light to the whole thing.