Through the startups indexes I’ve been creating in the past month I’ve developed a database of over 1,000 companies with dozens of signals each. This list includes ALL the startups in my database, across all the portfolios that have been indexed so far, ranked by momentum.

Of the 1,183 startups in the index 71% (844) exhibited positive growth in the month of April across the signals we are tracking.

Why I’m Writing These Posts

Many commenters and friends have asked why I’m doing this and not working on my startup. In case it wasn’t obvious, this is our startup and these posts are our MVP. I’d like to publicly acknowledge the tremendous effort by my team that make this possible. Kevin Morrill, our CTO and cofounder, who has taken a process managed in dozens on unwieldly spreadsheets and a ridiculous number of browser tabs and automated it with code. Andy Sparks, our Technology Editor, has undertaken the incredible schlep work of hand building new indices and researching startups, cleaning, curating and organizing our data.

How to Read This List
Momentum measures a quantity of motion, measured as a product of its mass and velocity. In case we want to measure the momentum of a startup (the “body”) where mass is the company’s share of web traffic (as measured by Alexa rank) and velocity is the growth trajectory of several different signals. Unlike previous indexes growth trajectory is now heavily weighted toward sustained growth, versus small spurts of growth from press coverage or a burst of paid traffic or Twitter/Facebook followers.

The Bigger They Come, the Harder They Fall

You will find companies in the top portion of the list that you’ve probably never heard of, and companies near the bottom who are big names you recognize right away. Because of this, you might be tempted to immediately discredit the entire index – but let’s walk through a few examples first so you can see what we are measuring. Since this measures momentum, the bigger the company the more it is impacted when it fails to grow.

#2 – Coinbase, a service for storing and selling Bitcoin e-currency, has been gaining a lot of momentum alongside the popularity of trading the online currency – averaging 11% growth week-over-week in web traffic by our estimates. This growth also shows in Coinbase’s social media following. They grew Facebook Likes 35% from 452 to 614 during April. On Twitter they grew from 1375 followers to 1876, a 36% growth rate. We’ll be watching to see if Coinbase can sustain this growth in May.

#1179 – StumbleUpon, the popular social content discovery service, appears just 6 positions from the bottom of the list and upon closer inspection we see this is because the mass of the company has declined as it dropped from 176 to 179 in Alexa rank during April. Based on our analysis this drop is representative of a loss of around 10,000 unique visitors per day, and a look at the companies Alexa graph reveals their traffic has been in steady decline for over a year.

Also of note in this list are some of the younger startups that have already shot to the top. YC Winter 13 companies such as Strikingly, Teespring and Thalmic Labs made an impressive showing.

Biggest Winners & Losers

Keep scrolling and you will find the entire list of startups, but for those of you who don’t like scrolling through 1000+ rows in a spreadsheet I’ve got the highlights for you.

20 Startup Who Gained the Most Momentum

  1. BuzzFeed
  2. News Blur
  3. Coinbase
  4. Dropbox
  5. Codecademy
  6. Disqus
  7. Rap Genius
  8. Weebly
  9. ROBLOX
  10. Priceonomics
  11. Strikingly
  12. Teespring
  13. Creative Market
  14. Aereo
  15. Virool
  16. BuildZoom
  17. Thalmic Labs
  18. Bitnami
  19. Perfect Audience
  20. Tapas Media

20 Startup Who Lost the Most Momentum

  1. ChirpMe
  2. Causes
  3. Payvment
  4. Udemy
  5. StumbleUpon
  6. Lockitron
  7. Svbtle
  8. Crowdbooster
  9. Grubwithus
  10. Kaleidoscope
  11. Oh Life
  12. SplashUp
  13. Tumult
  14. LaunchRock
  15. Ecomom
  16. FamilyLeaf
  17. Imgfave
  18. LeanMarket
  19. OpenX
  20. Iconfinder

The April 2013 Startup Index