Correction: Google is not trying to be a job board, or even get in the job board business.

Google Base is not trying to be a job board or even a classifeds system. They are not trying to sell houses or advertise jobs or sell cars. Google Base is a product that allows people to build websites and applications while uses Google as a database. The more content Google can analyze the more accuratly they can deliver more targeted ads on their other sites, where the real money is for them. In addition to letting developers use Google Base as a public or prive database, they are also allowing developers to build applications / websites that use the public content put into google base. Yes you can search base.google.com and find a pseudo job lists, but it will take a developer/company to build a true job board using all of that data. Basically you can build a job board and get tons of jobs automatically, without having to do any wrapping or indexing. The same goes for real-estate, cars and any other popular categories of data.

So in closing. Google is not getting in the job board business, Google is trying to be the literal hub of data / data transactional API on the internet. For example Flickr, who is very liberal with their data, could use google base to store all of their data - then any other company could use the Google Base API to create a Flickr browser plug-in. "All" Google really wants to be, is the database for all the information floating around the web.