At times I'm not completely sure about counting rows, especially when the terminology WITHIN A SINGLE PATTERN seems to vary. For example, what's the difference between "every second row" and "every other row"?

Also, is one supposed to treat selvedge stitches as if they aren't in the pattern? I bought a knitting book and the author went on and on about how important it was to knit every selvedge stitch twice and I had no idea what she was talking about. I had never heard of slipping the first stitch in every row, so what she was saying made no sense to me. Later I saw an E. Zimmerman video and she was talking about slipping the 1st stitch. This is supposed to make edges more even?

I can certainly understand why a continental knitter would want to knit in the round. I can't purl like that! I think the fact is that both type stitches are easiest when the yarn is coming up from the direction of feed, and so the knit sticth is easier by Continental; in american technique, I purl faster than I knit for that reason.

Sometimes a pattern will say 'every second knit row' or 'every second purl row,' which would essentially be every 4th row. Every other row is just that.
If a pattern says every second row, then it is every other row, and they should have had more coffee. :shrug:

Some patterns include selvedge stitches, and some don't. You can usually tell if the pattern ends and starts with a knit regardless of what's in between.
Other patterns don't call for one. I guess you can add one if you like, but I don't think it's essential.

I like to put them on scarves because it does leave a nicer edge, but I don't add one to sweaters that are going to be seamed unless the pattern calls for one.

I'm w/ Ingy on the selvedge stitch thing...no point really on sweaters unless it makes it easier for you to see the edge (which is possible I guess since it looks neater) but I think it's a must for scarves and baby blankets that have a garter border and whatnot. I'm working on a baby blanket now for a friend's sister who is due in about a month and I was just thinking yesterday that the selvedge makes the edges so nice--I typically shy away from garter edges on baby blankets but I loved this one so much and didn't feel like putting the thought into changing the style of edging.