If you're familiar with del.icio.us you will be familiar with the tag suggesting as-you-type support. The reason why, I believe, the tagging works so well within del.icio.us is that it helps you create a subset of tags that you commonly use for different types of links. This way, it makes it easier to find tagged [...]

If you're familiar with the del.icio.us tag search box, then you'll know it will grow with the length of the content you enter. This is particularly useful for search boxes or tagging entry boxes, though the only downfall (I think) of del.icio.us's entry box is that it can grow to become wider than the entire page [...]