Loadables is a system monitoring tool for Mac. It lists all the processes, plug-ins and libraries that are loaded on your Mac when you turn it on. These lists are divided into five different tabs.
Per-User Services lists all the services that are specific to the active user account. Your login items, which are the applications that you have set to start with your Mac, will be listed here. The second tab, System Wide Services, presents a list of all the system services. These can overlap with the per-user services. OSX Services lists all the services that are configured on your Mac, regardless of whether they are running or not. The following tab is called Mach Services, and these are core services provided by the running applications. Lastly, there is a list of other services. These are also system services, but they don't fall into a specific category.
When you click on a service, in any of the tabs, a pane will pop-up from the top of the screen. It will display information about the selected service, and in some cases, it will let you change configurations.
Loadables lets you disable and stop services, but as the warning displayed in the app states, this should be the last resort measure.