What Every Major Silicon Valley Investor Is Using To Find The Next Big Thing (businessinsider.com)

There are 600-800 VC's on Product Hunt and I know of at least three deals that have been sourced through the site:

1) Taptalk + SV Angel 2) Fitbay + Steadfast Ventures 3) Move Loot (YC) + Index Ventures

And I'm sure there are several others.