It likely comes as little shock that I tune in regularly to Done Deal Pro. If you've read any of our Logline Central posts, you will have gathered that I go there for all my info on what's recently sold, been picked up in turn around, or otherwise been acquired. If you get the trades - Variety or Hollywood Reporter - or read Deadline, you can get a lot of the same info, albeit maybe less of it than through the subscription-based DDP. Regardless of where you gather info on sales and acquisitions, if you're an aspiring writer, this is something that you should make a point of doing.
I find tracking sales invaluable. For one, it lets you know what the industry is leaning toward at the moment. We all witnessed the giant vampire crazy (which I hope is nearing its conclusion). Trends don't tend to last too long in Hollywood, so noting an uptick in vampire related scripts doesn't necessarily mean you'll have time to conceive of, write, and polish a vampire story of your own. It might, however, indicate that now would be a good time to show the world the vampire script that you have already written and deemed ready for the light of day (bad pun intended).
Tracking sales is also a great idea if you're beginning your query phase. Looking to land an agent for that big action thriller you're so jazzed about? See who is repping those kinds of sales now, and make sure you don't solicit someone who mainly deals with rom-coms. Hone your queries and chances are, you'll have better results. I was very specific in my outreach, and it paid off in forms of finding a manager.
Speaking of, managers and agents track sales, which is another reason you should. They are busy people. Presumably, writers are also busy people. But my experience with managers and agents is that they will take the time they need, but won't have much to spare. If it is 1998 and you say, "Hey, I have this great idea about a group of soldiers who have to go find another in WW2," your rep will say, "That's already in the works." If you were tracking sales, you would have known that. The similarity doesn't necessarily mean you have to stop writing that idea, but if you have yet to begin, you might want to put it on the back burner. Save them some time by reserving that pitch for later - you'll all appreciate it.
Most recently, I've been tracking sci-fi projects closely, as both of mine that are out there (post-Apocalyptic and the collaboration) fall heavily into that category. Unfortunately, two projects - one that is a film in theaters and one that was just announced - share more similarities with the sci-fi collaboration than my writing partner and I would like. Because of that, because we are tracking sales, we've decided to implement some large but not drastic changes going forward, so that we share fewer commonalities with these two projects. It's conceivable that the overlap won't wind up mattering, but if it's something we can avoid outright, then we decided that's what we should do. And that's just one more reason it's prudent to track acquisitions.