Hi Sunil,
These days I’m all about the writing but I do test affiliate links quite often still, it takes a little research to find good ones and I’m very picky about who I choose to affiliate with, they have to be in the tech niche and close to what I do. When it comes to Google penalties, I NEVER put more than one or two affiliate links throughout the entire site, that’s asking for trouble. Google will tolerate a couple but I wouldn’t recommend using them liberally such as textual links throughout blogs. Aside from anything else I feel that it really reduce the quality of the UX, it’s spammy and I personally never stay long on a site that has lots.
It’s about residual income, you’re never going to get rich doing it, so why risk your business and your reputation.
Rant over … the others, well I do teaching at a local level and when I find the time I intend to offer online as well, membership is another project that’s currently on the backburner for when that magical day arrives when I have the time. Mostly, my time is spent on writing as it’s my ‘first love’ and that covers everything that I’ve suggested.
Hope that helps, thanks for reading 