Well you can scrape using Scrapebox for web2.0 properties, which would allow you to post on specific properties that are supported by your posting tool if you have any?
All you need are some foot prints of the web2.0 properties that you are looking for, something like site:weebly.com or weebly does support a forum inside - look for regular occurrences on the forum , like a repeated text that clearly identifies it, and that will be your foot print.