WSN Software Directory comes with thousands of listings, but you'll notice that these listings have old information in them. You'll need to regenerate them in order to get the latest versions of the software reflected. Go to Admin Panel -> Maintenance -> Regenerate and check the "Do PAD file updates?" box. Please note this requires pulling up tens of thousands of web pages to read the PAD files so it will take several days -- leave it running in a background tab in your browser.
wget -O /dev/null "http://installpath/index.php?action=padupdatecron"
Reloading WSN's Repository
WSN provides two sets of softare data -- a human-moderated set of ~18,000 quality listings (courtesy of qarchive.org) and a larger unmoderated set. You can reload the moderated set by gonig to youradminpanelurl/loaddata.php?filled=1&datasource[0]=padlistingsalt&dataindex=0&part=0&dataindex=0 and the unmoderated set by going to youradminpanelurl/loaddata.php?filled=1&datasource[0]=padlistings&dataindex=0&part=0&dataindex=0
Be aware that you're wiping your site data in the process and starting over.
Reloading From Another Source
If you want to replace WSN's default set with a set of PADs you've found elsewhere, and you want to wipe the database before importing so that you only have the new prefered set, then go to Admin -> Miscellaneous -> Advanced and running these lines in the SQL box:
TRUNCATE TABLE {PREFIX}attachments;