If I'm using custom textures...

According to a thread on here about what I should do before releasing a wad, if I'm using custom textues I should provide a link to that texture set (such as gothictx.wad, which I am using for my map). Is this necessary? I can't just upload a single wad that contains the custom textures within it? I'll do whatever's expected, I'm just a bit confused because I'm new to mapping.

If you're using a freely distributable resource wad I don't see any reason why you can't just include the few textures you use with your own WAD, just indicate credit where credit is due in your readme file. The Doom community is one that is generally pretty relaxed and open about borrowing and improving upon each other's work.

I'm sure some authors might be touchy about their own personal work used in others' works, though, in which case if you're not sure you should check their own readme files or ask the authors themselves.