Creation of new features for the SocialEngine site

I need to create a module for downloading data from the site in the csv format. There are 3 types of activities on the site: Blogs, Polls and Forums. I have to be able to download the data (blog entries, poll answers, comments) from the site in csv format. It is a kind of activities report - I choose the activity I need, than I click "Download" button and as a result I have a table in csv format. This table will contain User, Date, Comment, etc columns.