I took the time to recommend some books that were very specific to the thread at hand, that I had taken the time to read and evaluate. Getting a few extra dollars to buy more books with, that costs those clicking nothing, seems like a mutually beneficial transaction in that it makes me more likely to read some interesting books I can recommend in the future.
So: yes, they were. If you don't like them, don't click on them. If you think my account is a spam account, created for the purpose of spamming HN with affiliate links, feel free to report it to Paul Graham.
I don't have a problem at all that you put in the affiliate link and didn't even notice it.
Otoh I think the disclaimer that you made above is good and informs people of why you did what you did so it might be an idea to include it. If the parent thought that, I'm sure others did as well. (Of course this might encourage others to do the same who don't put the same effort in that you did to read and evaluate.)
This is somewhat similar to when someone at a store makes a suggestion and adds "I'm not on commission". Here you are saying "I am on commission but I use this product and can vouch for it". Nothing wrong with that.
(I'd like a suggestion on a learning rails book by the way.)
The free Rails Guide is pretty good, actually! You could also get the Rails book with Sam Ruby as an author, but I'm less enthusiastic about it these days, mostly due to the fact that Rails has grown so much, so it covers a smaller set of the system, less comprehensively than it used to.
