In terms of graphic software, plug-ins allow us to extend our creativity. There are plug-ins specific to photos and photo editing. There are also plug-ins specific to graphics. Both PSP and PS come with a series of plug-ins unique to their own platform, although they will mimic one another. And most PS plug-ins can be used within PSP.
In computing, a plug-in is a set of software components that adds specificcapabilities to a larger software application. If supported, plug-ins enable customizing the functionality of an application.
And then there is the whole world of 3rd party plug-ins. You saw SBP in my last post. But there are many more out there, but for sale and free. The Bug will probably be adding a list of sites that offer plug-ins as well.
In the meantime you might want to take a look at the list that Bright Hub has amassed for PSP 3rd party plugins. She has links to the various plug-ins.
A free plug-in that I highly recommend is OptikVerve's Virtual Photographer. This is for photo manipulation.
So you see there are advantages to having plug-ins to work with in your scrapbooking.
Word of Note: In your documents folder, if one was not set up when you installed PSP, make a My PSP folder. Within that folder make an new one called 3rd party plug-ins. Put your plug-ins in that folder. In PSP>File>Preferences>File locations, browse for the 3rd party folder and add it. By doing this you will not slow your program down. Have fun.