Apple would do well to give us that option in the App Store Updates interface.
You can actually hide updates like you used to, it's just not very intuitive. You just need to right-click in the update space you want to hide, and it should say "Hide Update". I'd take a screen shot from my own machine, but I don't have any updates right now. This picture shows you what it should look like though.
What brought me here today is that I was surprised that the App Store updated Apple Remote Desktop Client for me today when I do not even have Apple Remote Desktop Client. Why in the world would they tell me that there is an update for it if I do not even have the program?
You do actually have the client software on your computer, everybody does, which is why everybody is getting this update. The client software is part of the OS. If you've ever used the "Screen Sharing" application before, you were using the client software. Or if you have a Mac at work and your support staff has ever taken control of your computer, they are using the client software. What not everybody has is the Admin part. That part is a piece of software you have to purchase from Apple that will allow you to perform various administrative tasks on remote computers. I use it everyday at my job and it's a tool I couldn't live without. I hope you don't get the constant reminders too, but the v1.1 update Apple put out yesterday seemed to do the trick for me. It fixed this particular problem on both the Macs I was having an issue with.