Maybe those who do that don't know how to use the "quote" tags... You can't expect users who don't even know how to send a PM be familar with HTML code

But I agree with you, it's really annoying, just as quoting pictures

(I noticed that on another forum, it's really crazy).
So, here's a quick course for those who don't know what Cimmy's talking about
:
When you quote a post, it appears between [ quote ] and [ /quote ] tags as part of the message you are to compose (w/o space, of course).
If you want to reply to a fraction of the message, simply delete the rest from between the tags, that's all. If you would like to devide it into smaller parts and reply one by one, put the part you want to reply to between similar tags, write your reply, and do the same to the next part... That easy