My agent hunt started badly. I submitted to a junior agent in a very well-regarded house. An email submission, with the agent citing a three week response time. After waiting three and a half weeks, I went to look at the agent's Publisher's Marketplace page - and found it gone.
A quick Google search told me that the first agent I had chosen to submit to after this long fallow period of non-submission had quit the agenting industry a week after I'd submitted to her.
Agent number two now submitted. Another email query with a theoretically fast turn-around and hopefully not resulting in her sudden departure from the industry.