I opened a new site on a brand new domain about a month ago. MSN and Google have already indexed many of the pages, but Yahoo is only spidering the home page. I don't have a ton of backlinks but a few and I'm getting more each week. Most of my pages validate XHTML 1.1 and I just recently removed PHP Session IDs completely to make the urls very clean. I don't have robots.txt blocking anything.
Is it normal for Yahoo to take this long before it starts deep crawling, or is there something else going on?