Activator lets you assign "shortcuts" to your device. Whether it's to quickly reply to a message, quickly compose an SMS, or remove background applications to stop eating your battery.
You can set Activator to work on your device, each action then is specified by what gesture is performed, and which application assigned to. If you want to be more specific, you can have Activator working at home screen only, whenever inside an application only or at lock screen only.
Home button and lock screen are your first choices of an Activator action. For example, you can set short hold on home button for Backgrounder, which lets you run apps in the background, but thats another tweak review ;)
Before updating to iOS 5, I used to have setup swipe from screen bottom left Activator action to kill background applications. That tweak is not yet compatible with iOS 5, I think (not sure).
All of these are pretty much self explanatory, once you tap on them they will take you to a list of certain apps you can apply to them. For instance, launching a certain app from your springboard.
Activator is available under the BigBoss repository, developed by Ryan Petrich, and it's free. Go get it if you don't have it!
Hope you liked this little tweak preview/review/show. Activator is a very usefull tweak, just make sure other tweaks won't interfere, then it's just a mess to clean up. I'll be trying to post up one or two blogs a day of some tweaks that I personally use on my phone and think are cool/great/usefull/necessary and another reason to jailbreak your iDevice :)
If you have any suggestions/comments/issues or any different way of having this setup for a more pleasant reading, let me know in the comments and I'll try my best to keep you all interested. More tweaks will come!