I've been meaning to do this forever, but am an excellent procrastinator and so have managed to hold off for a couple of years now. Still, the time may have come to actually go through and try to answer some of these collectively instead of individually.
On Replies: First, let me say that I love getting comments. I truly do. I read them all, and they honestly fuel me to keep coming back with my limited free time to draw and post pictures of multi-color ponies doing the things that multi-color ponies do. This fandom is wonderfully supportive, and I believe that is the key to its continuing success in general.
As a result, I do try to properly express my gratitude at receiving comments, especially for the days immediately following an image being posted. I genuinely like interacting with fellow fans. However, that limited free time thing tends to creep up on me... I do freelance work, and so can go from having nothing scheduled for the day to having a rush job with high stress at a moment's notice. Sometimes I can have long stretches with no constraints on my time, and others I can go months with seemingly unending assignments flowing into each other. So free time for a hobby like this can be very valuable, and even when the opportunity comes along for tackling some tasks (like typing all of this out) a little part of my brain says "You know... you could be using this time to draw ponies instead..." And I am weak when it comes to resisting this voice.
I also tend to do a lot of my online reading of comments in snippets on my phone or tablet at times when I'm not really in a good position to respond (and I hate typing on my phone.) I'll almost always put off replying to something I've read on my phone until I'm back in front of my desktop computer... Only by then new messages will have come in and pushed the older ones out of the front page of my inbox. (My message center is an absolute mess, by the way. It literally holds thousands of messages and notices, as I never really clear them away.)
Ultimately, this means that if you don't catch me in a replying spree, there's a good chance I will not get to replying. Generally, if you need a response from me, a note is the best way to go. I try to keep up with my profile page as well, although that often goes weeks before I get caught up with replying to those messages. In short, I'm not terribly reliable and I do feel remorse over it. Again, let me assure you that I do read all of the comments coming in, and love getting them. I apologize for everyone who asked a question directly which I never got around to answering, as well as anyone waiting for a gracious acknowledgement of their kind words that was never returned.
If it's any consolation at all, know that my family has all but given up on the idea that I'll ever reliably return e-mails, and the thought of me getting around to sending actual cards in the mail is likely laughable to them at this point.
On Commissions/Requests: Here we come back to that limited free time bit. I already get paid to draw things that other people want me to draw in my "day job". (I don't really talk about that job much... some of it is due to non-disclosure agreements, some of it is just general privacy. I promise you all that it's not usually terribly interesting stuff anyway.) In any event, drawing fan art like this is my hobby, something where I can say "I'm going to draw whatever I damn well please, and you can't stop me!" (I say this to nobody in particular, but it still lets me feel like a rebel.) So this leaves me reluctant to take a commission where I'm drawing ponies but need to worry about pleasing someone else specifically. For me, ponies mean no deadlines, and complete freedom to my own creative whims. Nothing kills the joy of drawing in my free time like realizing that I still need to finish a picture for so-and-so.
So I have always declined commissioned work and requests. In the future, that might change, and if it does I will be sure to do another journal post with the details and prices and all of that.
Now there are a few collaborations in my gallery that I have done with close friends for stories and the like, but even they have learned not to ask me to do art for something so much as try to tempt me into wanting to do it on my own.
On my "process" or what passes for such: I generally do most of the work in Photoshop (I'm still on CS2), as I have it for work purposes and it can do most everything I'll ever need to do, plus countless other things that I'll never bother messing with at all. In the last couple of years I have picked up a program called "Manga Studio EX 4.0" which I use to do my sketching and linework, as it produces a nice vector line that can compensate for my own cruddy penmanship. I then transfer the linework into Photoshop for coloring.
For a very rudimentary rundown of the process (likely only valuable to those beginning in digital art), I like to keep my character linework on an upper layer, and add the color to a layer beneath it, then have background layers beneath those. Once I've laid out the initial flat colors for a character, I can lock the transparent pixels of that layer (to keep everything within the lines) and go about adding shading and highlights. In general, I do very basic shading (darkening the colors around the edges of shapes) to flesh out the form, leaving the more precise highlights and shadows from set light sources in the image to come later. Depending on the impact I'm looking for, I can leave the linework black for a more graphic look, or lock the transparent pixels on that layer as well, leaving me free to paint over the black lines with any color I choose, resulting in colored linework and a look that more closely resembles animation and the show itself. Again, this is just the most basic version... My files on complex images tend to have way too many layers to easily make sense of. I need better discipline.
On the use of my artwork: I create nearly all of my fan artwork under a Creative Commons "share and share alike" license. In short, this means that, as long as you give me credit and don't pass it off as your own, and as long as you aren't making money off of what you use it for, you're welcome to use it in your own project. Fan fiction covers, videos, wallpapers, something physical you're making for your own use, or for a gift... go ahead. I wish you luck with them!
Now, there are plenty of people who tend to put up my work in their own galleries and such with no attribution, and sadly there are plenty of people at conventions and online who sell copies of my work without my knowledge. These are violations of the copyrights.
My mindset on it is basically this: The fandom originally took off because people took images, characters and such from the show and ran with them, building upon them and creating any number of new things. I think that's great, and I think my own artwork should be part of this communal pool feeding the fandom's creativity as well. So if it's something shared freely in this spirit, I'm generally all for it. However, unlike Hasbro, I don't already have an avenue for making money off of this work. I pour a lot of hours into them, and so seeing people steal the credit for them or profiting from them while I get nothing is rather depressing.
Hmmm... once again, that little voice is calling "this could be time spent drawing whatever you want", so I think I'll cut it off here for now. Hopefully, this will turn out to have been helpful to someone. At the very least, I hope that people will take away from this the fact that, despite my negligence, I do greatly appreciate everyone who takes the time to look at and especially to comment on my work! Thank you all.