there was a time, not so long ago, when we believed that most of our genome is made up of junk DNA which has no information content whatsoever. Kind of rings true in this day and age, when most of our email is spam, and most of our post is junk mail.
However, it is now getting clearer that much of the presumed junk contains functions that we simply don't understand. The ENCODE project has been sifting through the junk DNA with all methods imaginable and in June they presented a pilot study based on just 1 % of the genome, suggesting that there is loads of interesting stuff hidden in the junk.
Am doing something about this, and have just finished reading their Nature paper (vol 447, p. 799), which was one of the most difficult papers I've ever managed to read. 18 pages of TSSs, TxFrags, Un.TexFrags, etc. (Well, it is nicely organised, but if you throw one hundred methods of molecular biology at 30 million basepairs, the results are bound to be complex.)
Fascinating stuff, but I think I will skip the 28 companion papers published simultaneously in Genome Research :)