Birdly - Birdly is an expense management and expense report solution for SMBs.
Question2Answer - A Q&A site helps an online community to share knowledge.
PushMarket - Automate personalized emails for ecommerce (YC15)
Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
Dynamic Campaigns by Sigstr - Share the most relevant content in every email
The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.