I have a suggestion that seems easy.

After clicking on someone's name and you are looking at their profile: could there be a link that showed their posting history. That is the link takes you to the search function and enters their username for you. I realize that this can be done on one's own, but first you have to copy their username, search on something, once in the search function you have to delete what you searched on, click on the advanced search and then paste their username.

I thought maybe there should be a suggestion thread that could be stickied. I looked on the first page and didn't see anything similar.