We see this type of spam-bot a lot. They make seemingly innocent posts (which are often slightly incoherent as it seems they assemble them from snippets of other posts, as macgeek417 said) but have a link to a spam website in their signature. This is purely to increase the Google page ranking of their website, since that is based on the number of incoming links from other websites. So each post that they manage to get their signature link in to helps to increase their ranking. Of course we're not going to remove the account of every member who signs up and puts a link in their sig. However, some (like that one) are clearly spam.
Also, can I please remind everybody of the final clause in the Forum Rules:
Also, can I please remind everybody of the final clause in the Forum Rules: