Selling services like support or consulting is fine, since that's generally independent from FOSS licensing/copyright concerns. Anyone can do that though, not just the creator or contributors. For example, there are lots of third party database consultancies that offer support for major databases, both FOSS and commercial.
Customization is also fine, but the purchaser of the customization must still abide by the AGPL: the end-users of the customized software need access to the customized codebase. If the customized product is only being used internally (e.g. for employees of the company that purchased the customization) then there's no problem. But if they're offering it in an externally-facing SaaS, or embedding it in externally-distributed software, the customized code must be made available to the end-users of the software.
With FOSS often it's simpler to do this as "sponsored development" where someone pays for a new feature to be made directly upstream, rather than having a customized fork.
That all said, services and customization are generally difficult to scale as a business. Even with a fairly large userbase, the percentage of companies who are willing to pay for support or customization tends to be disappointingly low.
Selling services like support or consulting is fine, since that's generally independent from FOSS licensing/copyright concerns. Anyone can do that though, not just the creator or contributors. For example, there are lots of third party database consultancies that offer support for major databases, both FOSS and commercial.
Customization is also fine, but the purchaser of the customization must still abide by the AGPL: the end-users of the customized software need access to the customized codebase. If the customized product is only being used internally (e.g. for employees of the company that purchased the customization) then there's no problem. But if they're offering it in an externally-facing SaaS, or embedding it in externally-distributed software, the customized code must be made available to the end-users of the software.
With FOSS often it's simpler to do this as "sponsored development" where someone pays for a new feature to be made directly upstream, rather than having a customized fork.
That all said, services and customization are generally difficult to scale as a business. Even with a fairly large userbase, the percentage of companies who are willing to pay for support or customization tends to be disappointingly low.