The topic of web development is extremely broad, and since we also have the Webmasters.SE site, anything related to the general discussion of web development should be asked there instead. It seems that this tag just gets added onto questions which are about websites, when it really has no meaning whatsoever.
From the Pro Webmasters FAQ:
What kind of questions can I ask here?
Pro Webmasters - Stack Exchange is for professional and enthusiast webmasters. If your question generally covers the operation of websites which you control, then you’re in the right place to ask your question!
Pro Webmasters has nothing to do with web development, it's for operators of websites, not developers, good questions on web development should be asked on Stack Overflow or Programmers, depending on perspective. Worth noting that general discussion of web development would be off topic for any Stack Exchange site, although I think you didn't really meant general discussion (poor choice of words, perhaps?).
That said the tag is a meta tag and I couldn't find a single question that benefits from it - didn't try very hard though, quickly browsed the first couple of pages of web-development questions. The tag has 18,671 questions currently and I don't think we can clean it by hand, so if the tag is indeed deemed worthless, we'll need some help from the team to eradicate it.