I find the business model fascinating and it is amazing to watch them scale. My family business used to spend over $20k per year on YellowPages ads which drove about 8-12 calls per day at a very high close rate. As YellowPages has died off the money has been invested in an online presence but the skill required to design the site, keep it updated, and to manage all the online advertising spend is well beyond a normal person.

The fragmentation impact of having your customers looking for your services in dozens of different ways vs opening the phone book is costly and complex to overcome.

Once you pay a designer, hosting provider, and then pour the rest into Adwords it is very hard to get the same 8-12 calls per day with $20k of annual spend.

Thumbtack are helping solve that problem and syphoning all the money these businesses used to spend on YellowPages or are wasting on poor Adwords bidding strategies. Paying per lead is not that much different from paying $20k to YellowPages who give you no guarantee you will ever get a phone call.