Regarding the FULL vs LITE version:
The Lite version is designed to only be used by folks manually creating their backlinks. There is no automation - for example: you go out, post a blog, and then you can manually enter this information into SERPAssist Lite. Keeping track of user names, password, URLs, and whether you pinged is all included - but YOU are doing these tasks.
The FULL version is designed to automate all the tasks. Create email profiles, create Web 2.0 accounts, post to the Web 2.0 blog, *EDIT* existing posts, generate profile and social bookmark backlinks, spin content, etc. etc.
Basically, SERPAssist was initially designed to just help you visualize your backlink efforts. It continued to grow in terms of features and I decided to split them into two editions - and give the Lite version away for free.