I don't see much of a point in dell - it seems to be used for all manner of things that really aren't Dell-specific, from networking issues to power problems to OS-specific questions to power management surprises. There might be Dell support people on the site, but in the current way dell is used, nobody can be an expert in it. It would be nice if we could get dell to be used only for things that are actually directly caused by or related to Dell hardware, but at the moment, people are just slathering it on anything incidental to Dell.
I think the Dell model tags, however, actually have some usefulness. Model tags should (in my opinion) be used for hardware servicing questions on those models. Machine models can have certain idiosyncrasies, properties, and problems. It is entirely conceivable that somebody could be an expert on the dell-inspiron's hardware, and I would be open to retagging such dell questions to carry the model tag.