Respectfully, OP; I disagree.

I appreciate authors making announcements, but I feel like authors promoting their work would make them (and me as a reader) uncomfortable if they promoted with a direct appeal to readers like what you're describing.

Having said that, there used to be this girl who ran a Youtube-cast (not sure if she does anymore) and she would ask authors prepared questions live and on camera. That was pretty neat. I don't need the camera necessarily as I think it could work even better as a podcast (more authors willing to participate and better editing to remove long pauses and to correct issues). I know that I made some purchases off of that. . . but if authors were making direct appeals instead of announcements, I'd probably leave the sub. Why is it okay with an intermediary? Well, it is just part of the social contract. . . people being asked about their work gives them permission to politely talk about it. Also, the questions allow them to have something substantive to say instead of it coming off as a pushy or desperate salesman begging for our money.

Having said that, I do think some of them could do a better job providing links.