After playing around with vanitygen and spending a while looking for "available" vanity addresses by searching blockchain.info I discovered that already a very large number of plain english words have single tx's with a 0.00000001 BTC balance.
To get a good idea of what I'm referring to take a look at the following tx:
http://blockchain.info/tx-index/1009186/4e7b84a7ee19b7ea9f2d69fcb2734fb096cb012b413f8897b4f42871b225fabaSo it seems to me that someone went rather gung ho with vanitygen to try and own all the simple "firstbit" addresses they can possibly get. But what really can you do with them?
(maybe I can expect to see small amounts appearing in my wallet from these addresses after this post)
1WhoaKiRPrZWRWxjCcs4J2NTnyM9nezTq
1LikEsho5kfz1Ex9pw4keH9DYQ6S9gAWNH
1siLLyaisPRd8BsKsxmikSMkuw3KpxDh6
1PoStsmYCvbqsFJxdKC1h8gyhBEJLvAcN8
1LiKEc4Zx9AKcxT6xnYjtXzexweSwEYwpL
1TheSen7LCVi7dWW3hFN14SG2zn3MNdbM