Our 5 favorite startups at TechCrunch Disrupt

Right now, the TechCrunch Disrupt judging panel is choosing the top startup from among the 27 companies that launched on-stage at the conference over the last three days. But VentureBeat’s writers watched (and wrote about) every single one of those presentations, and we have our own favorites.

Digg founder: We let Digg stagnate

Digg, the pioneering social-news site which lets users vote on top headlines, began to lose momentum during the recession because it pulled engineers from designing new site features to work on improving revenue, founder Kevin Rose said today.

MobilePay lets you pay by card, without your card

MobilePay offers consumers a way to pay by credit or banking card without having your physical card on hand by linking it to an iPhone app that automatically authenticates with vendors to transfer payment. The service is going into closed beta today after operating in stealth mode for the past couple of months, it announced today at TechCrunch Disrupt in San Francisco.

Opzi demos Quora-like Q&A platform for businesses

Opzi, which provides a question-and-answer platform similar to Quora for enterprise customers, is betting that companies relying on email and services like Salesforce’s Chatter for quick answers have exhausted employees to the point of jumping on board the service. Opzi founder Euwyn Poon demoed the product at TechCrunch Disrupt in San Francisco today.