Through manual detective work, Ryan Hoover was able to confirm that three companies (out of the several thousand that have appeared on ProductHunt) raised funding after being discovered on ProductHunt. Instead of doing the same sort of detective work, the OP, on the other hand, wrote up a post with a broad, bold claim, put together a bunch of statistics unrelated to validating said claim, and then added the caveat that her statistics did not show the causation her claim required.
Put simply, to establish that ProductHunt is widely being used for deal sourcing, you would need to contact the startups and/or investors and ask them. At that point, you could compare the number of startups that have appeared on ProductHunt to the number of deals that were sourced through ProductHunt and draw a legitimate, meaningful conclusion about ProductHunt's popularity as a sourcing tool.
If you're going to make what amounts to a causation claim ("ProductHunt Is Quickly Becoming the Hot New Destination for Sourcing Startup Investment Opportunities"), noting at the end of a long post that you have no evidence of causation is kind of silly.