The participating services section in the bug bounty policy of a program includes a detailed list of the included domains that are in the scope of testing. This is a very explicit section and one of the most important sections in a bug bounty program and should be analyzed very carefully. Typically, the domains that are listed in a program are written as testingsite.com and if the subdomains are also included, the details are in *.testingsite.com. The longer the list of subdomains in this section, the more chances there are of finding a vulnerability in the program. Another thing to keep in mind is to keep a close eye on this section as programs frequently update this section of the policy to include new targets and domains. Bug bounty programs are generally first come, first served. If the bug bounty program updates its scope and you are the first one to know about it, it is highly likely that you will find a number of critical vulnerabilities in that domain. However, that being said, it is advised that you test each domain thoroughly with full concentration to look into critical vulnerabilities.