I have tried thumbtack for a few months and bought a package of $85 ($1.50 per credit) credits. After bidding to several requests I have got 0 replies.
Unfortunately I have just found out that Thumbtack allow any person send inquires by using only an email and a name. Thus Thumbtack doesn't ask enough information to verify people. For example a compulsory phone number and address.
Each request will generate an inquiry that other 5 professionals will bid. So assuming that each bid is $10, Thumbtack will make a profit of $50, whilst each professional will waste their money.
Reviewer is in unhappy mood. Please immediately contact the author of this review to discuss bad quality of thumbtack leads and associated monetary loss in the amount of $85. Thumbtack needs to issue a full refund according to poster's claims.