First of all, I to was a bit frustrated at the new search engine. However, now that I have learned to use it, I like it. But to answer your question, go to about page five of this forum(Q&A) and look for a thread titled, "How is the new RCU search function working for you." For some reason I can't copy and paste the link here(my wonderful, new and updated IE8). There are some good bits of info spread amongst some complaining. Also, click on the yellow search box toward the top of this page, then click the "more help" link that shows up there. Now will open a page that has all the directions.

One example: Suppose I wanted to see all the posts you have made on RCU. I would just enter in the search box, username:"Nitrodan73"

The search function works and like a new computer, once you play with it a bit, you'll probably like it.