Google trends is great for tracking the frequency of search terms over time.  Reports from industry analists put gift card sales down only moderately (5%) for the last two holiday seasons, but searching Google Trends for “gift cards” gives us a different picture, with traffic declining what appears to be about 30-40% from the peak on 2007:

The search term “visa gift card” seems to have suffered even worse:

The concept of selling unwanted gift cards however, has gone from non-existent in 2006 and continues to grow: